Technical Articles

How twitter works?

2009-02-09T14:08:00.000-08:00

Many social networking Web sites have lots of bells and whistles. Sites like MySpace and Facebook let users build profiles, upload pictures, incorporate multimedia, keep a blog and integrate useful or bizarre programs into homepages. But one Web company with a very simple service is rapidly becoming one of the most talked-about social networking service providers: Twitter.

Photo courtesy Twitter, Inc.
You can log on to Twitter through your phone, a third-party application or here, on Twitter's Web site.

So what does Twitter do? When you sign up with Twitter, you can use the service to post and receive messages to a network of contacts. Instead of sending a dozen e-mails or text messages, you send one message to your Twitter account, and the service distributes it to all your friends. Members use Twitter to organize impromptu gatherings, carry on a group conversation or just send a quick update to let people know what's going on.

Just Make It ShortSome people call Twitter micro-blogging -- very short messages. Users can update people about what's going on, like a blog, but the messages themselves are limited in length by system constraints.

Twitter's history is entwined with a few other Internet companies. Twitter's founders are Evan Williams, Biz Stone and Jack Dorsey. A few years before Twitter was born, Williams created Blogger, a popular Web journal service. Internet giant Google purchased Blogger, and Williams began to work directly for Google. Before long, he and Google employee Stone left the Internet giant to form a new company called Odeo.

Kara Andrade/AFP/Getty Images
Biz Stone (left) and Jack Dorsey are co-founders of San Francisco-based Obvious, the 10-person startup behind the popular Twitter social messaging service.

Odeo is a podcasting service company. According to Williams, he didn't have a personal interest in podcasting, and under his guidance, the company temporarily lost focus. However, one of Odeo's products was just beginning to gather steam: Twitter, a new messaging service. Stone gave Twitter its name, comparing the short spurts of information exchange to the chirping of birds and pointing out that many ring tones sound like bird calls [source: San Francisco Chronicle].

As the service became a more important part of Odeo, Stone and Williams decided to form a new company with Twitter as the flagship product. Williams bought out Odeo and Twitter from investors, then combined the existing company and service into a new venture called Obvious Corporation. Jack Dorsey joined the team and began to develop new ways for users to interface with Twitter, including through computer applications like instant messaging and e-mail. In March 2006, Twitter split off from Obvious to become its own company, Twitter Incorporated.

In this article, we'll learn about Twitter's application programming interface (API). We'll find out what a Tweet is and all the different ways you can create and read them. We'll also look at how Twitter can interact with mobile devices like cell phones.

Video Gallery: SMS Text MessagesTwitter's messages travel to mobile devices using the SMS text message protocol. In this video from Medialink, Ben Cook, the recently crowned world champion of text messaging, races against Nuance Mobile Dictation, the speech recognition technology that allows mobile phone users to enter messages using speech. See how texting and short message service (SMS) work.

What are Tweets?

Simply put, a Tweet is a message sent on Twitter. To send or receive a Tweet, you have to create a free account with Twitter. You also need to have friends and contacts with Twitter accounts -- otherwise you're typing to the void. Of course, you could use Twitter as a blog and keep all of your Tweets public, meaning anyone could read them on your personal Twitter profile page. But if you want to use Twitter as a way to keep in touch with friends, you'll need to convince them to sign up, too.

Photo courtesy Twitter, Inc.
Twitter's time line displays the latest public Tweets sent across the network.

Once you have an account, you can begin building your network of contacts. You can invite other users to receive your Tweets, and you can follow other members' posts. As you receive Tweets, you may discover you're looking into only part of a conversation. You'll see your contact's posts, but if he or she is sending messages in response to someone who isn't in your network, you won't see the other person's messages.

Tweets have a few limitations, mostly due to the fact that Twitter's design relies heavily on cell phone text messages. Tweets can only have up to 140 characters before the system cuts off the rest of the message for cell phone users. Members can read full Tweets on their Twitter Web pages or by using a third-party developer's desktop or Web-based application.

Tweets can only contain text -- members can't include pictures, video or other computer files with Tweet messages. Members who want people in their network to look at multimedia content must find a Web page to host the files, then send a message containing the page's address to their networks. Twitter converts all addresses more than 30 characters in length into tiny URLs -- links that compress the full Web site address to conserve space.

Twitter makes it easy to opt into or out of networks. If you join Twitter and find that you're being bombarded by Tweets from a particular member, you can choose to stop following his or her feed. All you have to do is send a message to Twitter that says "off," plus the chatty member's user name. Later, if you find that you miss the sender's updates, you can type "follow," plus the user's name. As long as the sender has kept you in his or her network, you'll start receiving those messages again.

Twitter's API

Twitter bases its application programming interface (API) off the Representational State Transfer (REST) architecture. REST architecture refers to a collection of network design principles that define resources and ways to address and access data. The architecture is a design philosophy, not a set of blueprints -- there's no single prescribed arrangement of computers, servers and cables. For Twitter, a REST architecture in part means that the service works with most Web syndication formats.

Web syndication is a pretty simple concept: An application gathers information from one source and sends it out to various destinations. There are a few syndication formats used on the Web. Twitter is compatible with two of them -- Really Simple Syndication (RSS) and Atom Syndication Format (Atom). Both formats retrieve data from one resource and send it to another.

Speaking Twitter's LanguageBoth RSS and Atom are based on the Extensible Markup Language (XML) format. Markup languages identify structures within data formats called documents. XML doesn't have a strict set of rules: It complements other languages like Hypertext Markup Language (HTML) by adding tags to describe the data within documents. The tags aren't visible to humans; programmers use them so that computers can identify and manipulate the data within a document. To learn more about how computers read tags and markup languages, read How Web Semantics Work.

Both Web syndication formats compatible with Twitter consist of a few lines of code. A Web page administrator can embed it into the code of his or her site. Visitors can subscribe to the syndication service -- called a feed -- and receive an update every time the administrator updates the Web page. Twitter uses this feature to allow members to post messages to a network of other Twitter members. In effect, Twitter members subscribe to other members' feeds.

By allowing third-party developers partial access to its API, Twitter allows them to create programs that incorporate Twitter's services. Obvious Corp's applications include desktop feed reader programs that let users post and retrieve messages on Twitter's network using a simple, independent interface. Current third-party applications include:

Twitterlicious and Twitterific, two applications that allow users to access Twitter through desktop applications on PCs and Macs, respectively

Photo courtesy Iconfactory
Twitterific is a desktop application developed by the Iconfactory for Mac computers.
OutTwit, a Windows application that allows users to access Twitter through the Outlook e-mail program
Tweet Scan, which allows users to search public Twitter posts in real time using either a customized search engine or Firefox's search box.
Twessenger, which integrates with the Windows Live Messenger 8.1 instant messenger program

Twittervision, which integrates a Twitter feed into Google Maps. You can watch public posts go live through a world map

Photo courtesy David Troy
Twittervision is a third-party application that lets you read public Tweets as they pop up around the world.

Flotzam, which integrates Twitter with Facebook, Flickr and blogs
iTunes to Twitter, an application for Mac computers that broadcasts the title of the song currently playing in the user's iTunes to his or her network
TwitterBox, a Twitter application that works inside the virtual community of Second Life

That's just a small sample of Twitter applications available, and developers introduce new ones every day.

Twitter on Your Cell Phone

From the beginning, Twitter's founders designed the service to work with the Short Message Service (SMS) protocol. SMS allows you to send and receive text messages from a cell phone to other phones and services like Web sites, voice-mail systems and e-mail servers. When you send a text message from your phone to Twitter, the message transmits to a mobile switching center (MSC), which sends the signal to a signal transfer point (STP). From there, the message goes to a short message service center (SMSC), which then sends the text to Twitter. Twitter sends the message back out to the people in your network using the same process in reverse.

The SMS protocol has several restrictions, which are the source of Twitter's limitations. An SMS message has an upper limit of 160 characters and can't include anything other than text. While there are other protocols that can send more information than SMS, they aren't as widely supported by cell phone service providers. By limiting messages to the SMS format, Twitter is able to reach a larger customer base.

Photo courtesy Twitter, Inc.
Your Twitter profile logs all of the Tweets you receive on your cell phone or mobile device.

One potential headache for Twitter is SMS spoofing -- a technique that allows someone to post messages from another person's cell phone number. In the early days of SMS messaging, this was pretty easy to do: Many cell phone service providers allowed people to send messages from an online form to a cell phone. One of the fields in the form was "from," and people could put anything they wanted in the field. A mischievous person could enter your phone number in the "from" field and send a message to Twitter. Your Twitter page would receive these fake messages -- as would everyone in your network -- as if you had legitimately posted them. There aren't many sites that allow this kind of messaging anymore, but several Web pages specifically designed to spoof SMS messages have appeared. Spoofing hasn't become a big problem on Twitter yet, but if that changes, the company may have to look into ways to prevent it in the future.

Twitter will also send messages over SMS to cell phones even if you use a desktop or Web-based application to post your Tweet. When you post your message, you tell Twitter to send the message out to all the appropriate outlets through the syndication format. Twitter sends the Tweet out to the cell phones of anyone in your network who has added a cell phone number to his or her Twitter account. For other users, the message may only appear on a Web page or in a computer desktop application.

Twitter members in the United States can interact with the service through their cell phones by sending text messages to 40404. In Canada, the code is 21212, and in the United Kingdom, you'll give your fingers a workout with the code +44 7624 801423. Through text messages, you can subscribe to other members' feeds, turn off feeds, add friends to your network or even delete your account.

Follow the MoneyTwitter doesn't charge members any fees, but really active Twitter members using mobile devices may get a bill from cell phone service providers -- most plans set limits on the number of text messages customers can send and receive. Twitter doesn't include advertising on Tweets or on Twitter Web pages, so it doesn't generate advertising revenue. In fact, the only way Twitter currently makes money is through private investments from venture capitalists. Twitter co-founder Biz Stone has even said that the company has no business plan [source: BBC].

Twitter's popularity appears to be on the rise. While the company hasn't found a way to monetize its services yet, many think it's only a matter of time before it finds a way to make Tweets profitable. Even if the service never turns a profit, it has served as an important role in online social networking -- what many Internet experts see as the future of the Web.

Source : How Stuff Works.

Social network service

2008-09-29T18:59:00.000-07:00

Social network service
From Wikipedia, the free encyclopedia

A social network service focuses on building online communities of people who share interests and activities, or who are interested in exploring the interests and activities of others. Most social network services are web based and provide a variety of ways for users to interact, such as e-mail and instant messaging services.

Social networking has created powerful new ways to communicate and share information. Social networking websites are being used regularly by millions of people, and it now seems that social networking will be an enduring part of everyday life. The main types of social networking services are those which contain directories of some categories (such as former classmates), means to connect with friends (usually with self-description pages), and recommender systems linked to trust. Popular methods now combine many of these, with MySpace and Facebook being the most widely used in North America;[1] Bebo,[2] MySpace, Facebook and Hi5 in parts of Europe;[3] Orkut and Hi5 in South America and Central America;[4] and Friendster, Orkut, and Cyworld in Asia and the Pacific Islands.

There have been some attempts to standardize these services to avoid the need to duplicate entries of friends and interests (see the FOAF standard and the Open Source Initiative), but this has led to some concerns about privacy.

The notion that individual computers linked electronically could form the basis of computer mediated social interaction and networking was suggested early on [5]. There were many early efforts to support social networks via computer-mediated communication, including Usenet, ARPANET, LISTSERV, bulletin board services (BBS), and EIES: Murray Turoff's server-based Electronic Information Exchange Service (Turoff and Hiltz, 1978, 1993). The Information Routing Group developed a schema about how the proto-Internet might support this.[6]

Early social networking websites included Classmates.com (1995), focusing on ties with former school mates, and SixDegrees.com (1997), focusing on indirect ties. User profiles could be created, messages sent to users held on a “friends list” and other members could be sought out who had similar interests to yours in their profiles.[7] Whilst these features had existed in some form before SixDegrees.com came about, this would be the first time these functions were available in one package. Despite these new developments (that would later catch on and become immensely popular), the website simply wasn’t profitable and eventually shut down.[8] It was even described by the website’s owner as "simply ahead of its time."[9] Two different models of social networking that came about in 1999 were trust-based, developed by Epinions.com, and friendship-based, such as those developed by Jonathan Bishop and used on some regional UK sites between 1999 and 2001.[10] Innovations included not only showing who is "friends" with whom, but giving users more control over content and connectivity. By 2005, one social networking service MySpace, was reportedly getting more page views than Google, with Facebook, a competitor, rapidly growing in size.[11] In 2007, Facebook began allowing externally-developed add-on applications, and some applications enabled the graphing of a user's own social network - thus linking social networks and social networking.[12]

Social networking began to flourish as a component of business internet strategy at around March 2005 when Yahoo launched Yahoo! 360°. In July 2005 News Corporation bought MySpace, followed by ITV (UK) buying Friends Reunited in December 2005.[13][14] Various social networking sites have sprung up catering to different languages and countries. It is estimated that combined there are now over 200 social networking sites using these existing and emerging social networking models,[15] without counting the niche social networks (also referred to as vertical social networks) made possible by services such as Ning and KickApps.[16]

Research on the social impact of social networking software

An increasing number of academic commentators are becoming interested in studying Facebook and other social networking tools. Social science researchers have begun to investigate what the impact of this might be on society. Typical articles have investigated issues such as

* Identity[17]
* Privacy[18]
* E-learning [19]
* Social capital[20]
* Teenage use[21]

A special issue of the Journal for Computer-Mediated Communications was dedicated to studies of social network sites. Included in this issue is an introduction to social network sites.[22] A list of academic scholarship on these sites is also available.[23]

Social networks connect people at low cost; this can be beneficial for entrepreneurs and small businesses looking to expand their contact base. These networks often act as a customer relationship management tool for companies selling products and services. Companies can also use social networks for advertising in the form of banners and text ads. Since businesses operate globally, social networks can make it easier to keep in touch with contacts around the world.

One example of social networking being used for business purposes is LinkedIn.com, which aims to interconnect professionals. It claims to have more than 20 million registered users from 150 different industries.

Professional networking sites function as online meeting places for business and industry professionals. Other sites are bringing this model for niche business professional networking.

Virtual communities for business allow individuals to be accessible. People establish their real identity in a verifiable place. These individuals then interact with each other or within groups that share common business interests and goals. They can also post their own user generated content in the form of blogs, pictures, slide shows and videos. Like a social network, the consumer essentially becomes the publisher.

A professional network is used for the business to business marketplace. These networks improve the ability for people to advance professionally, by finding, connecting and networking with others. Business professionals can share experiences with others who have a need to learn from similar experiences.

The traditional way to interact is face-to-face. Interactive technology makes it possible for people to network with their peers from anywhere, at anytime in an online environment. Professional network services attract, aggregate and assemble large business-focused audiences by creating informative and interactive meeting places.

Medical applications

Social networks are beginning to be adopted by healthcare professionals as a means to manage institutional knowledge, disseminate peer to peer knowledge and to highlight individual physicians and institutions. The advantage of using a dedicated medical social networking site is that all the members are screened against the state licensing board list of practitioners.[24]

The role of social networks is especially of interest to pharmaceutical companies who spend approximately "32 percent of their marketing dollars" attempting to influence the opinion leaders of social networks.[25]

A new trend is emerging with social networks created to help its members with various physical and mental ailments. For people suffering from life altering diseases, PatientsLikeMe offers its members the chance to connect with others dealing with similar issues and research patient data related to their condition. For alcoholics and addicts, SoberCircle gives people in recovery the ability to communicate with one another and strengthen their recovery through the encouragement of others who can relate to their situation. Daily strength is also a website that offers support groups for a wide array of topics and conditions, including the support topics offered by PatientsLikeMe and SoberCircle.

Social networks for social good

Several websites are beginning to tap into the power of the social networking model for social good. Such models may be highly successful for connecting otherwise fragmented industries and small organizations without the resources to reach a broader audience with interested and passionate users. Users benefit by interacting with a like minded community and finding a channel for their energy and giving. [26] Examples include SixDegrees.org,TakingITGlobal and Network for Good. The charity badge is often used within the above context.

Typical structure of a social networking service

Basics

In general, social networking services allow users to create a profile for themselves, and can be broken down into two broad categories: internal social networking (ISN)[27] and external social networking (ESN)[28] sites, such as Orkut,MySpace, Facebook and Bebo. Both types can increase the feeling of community among people. An ISN is a closed/private community that consists of a group of people within a company, association, society, education provider and organization or even an "invite only" group created by a user in an ESN. An ESN is open/public and available to all web users to communicate and are designed to attract advertisers. ESN's can be smaller specialised communities (i.e. linked by a single common interest eg TheSocialGolfer, ACountryLife.Com, Great Cooks Community) or they can be large generic social networking sites (eg MySpace, Facebook etc). However, whether specialised or generic there is commonality across the general approach of social networking sites. Users can upload a picture of themselves, create their 'profile' and can often be "friends" with other users. In most social networking services, both users must confirm that they are friends before they are linked. For example, if Alice lists Bob as a friend, then Bob would have to approve Alice's friend request before they are listed as friends. Some social networking sites have a "favorites" feature that does not need approval from the other user. Social networks usually have privacy controls that allows the user to choose who can view their profile or contact them, etc.

Several social networks in Asian markets such as India, China, Japan and Korea have reached not only a high usage but also a high level of profitability. Services such as QQ (China), Mixi (Japan), Cyworld (Korea) or the mobile-focused service Mobile Game Town by the company DeNA in Japan (which has over 10 million users) are all profitable, setting them apart from their western counterparts.[29]

Additional features

Some social networks have additional features, such as the ability to create groups that share common interests or affiliations, upload or stream live videos, and hold discussions in forums. Geosocial networking co-opts internet mapping services to organize user participation around geographic features and their attributes.

There is also a trend for more interoperability between social networks led by technologies such as OpenID and OpenSocial.

Business model

Few social networks currently charge money for membership. In part, this may be because social networking is a relatively new service, and the value of using them has not been firmly established in customers' minds.[30] Companies such as MySpace and Facebook sell online advertising on their site. Hence, they are seeking large memberships, and charging for membership would be counter productive.[31][32] Some believe that the deeper information that the sites have on each user will allow much better targeted advertising than any other site can currently provide.[33] Sites are also seeking other ways to make money, such as by creating an online marketplace (Facebook's Marketplace)[34] or by selling professional information and social connections to businesses: such as LinkedIn.[35]

Social networks operate under an autonomous business model, in which a social network's members serve dual roles as both the suppliers and the consumers of content. This is in contrast to a traditional business model, where the suppliers and consumers are distinct agents. Revenue is typically gained in the autonomous business model via advertisements, but subscription-based revenue is possible when membership and content levels are sufficiently high.[36]

Other business models such as including digital goods (personalization, avatars, background music, skins, gifts, etc.),[37] connection with casual games (on QQ in China[38] or Mobile Game Town in Japan), or link to mobile first made successful in Asia.[39] QQ's revenues in 2007 were US$523 million[40] and a US$225 million profit.[39]

Privacy

On large social networking services, there have been growing concerns about users giving out too much personal information and the threat of sexual predators. Users of these services need to be aware of data theft or viruses. However, large services, such as MySpace, often work with law enforcement to try to prevent such incidents.

In addition, there is a perceived privacy threat in relation to placing too much personal information in the hands of large corporations or governmental bodies, allowing a profile to be produced on an individual's behavior on which decisions, detrimental to an individual, may be taken.

Furthermore, there is an issue over the control of data - information having been altered or removed by the user may in fact be retained and/or passed to 3rd parties. This danger was highlighted when the controversial social networking site Quechup harvested e-mail addresses from users' e-mail accounts for use in a spamming operation.[41]

In medical and scientific research, asking subjects for information about their behaviors is normally strictly scrutinized by institutional review boards, for example, to ensure that adolescents and their parents have informed consent. It is not clear whether the same rules apply to researchers who collect data from social networking sites. These sites often contain a great deal of data that is hard to obtain via traditional means. Even though the data are public, republishing it in a research paper might be considered invasion of privacy.[42]

Notifications on social networking websites

There has been a trend for social networking sites to only send out only 'positive' notifications to users. For example sites such as Bebo, Facebook and Myspace will not send notifications to users when they are removed from a person's friends list. Similarly Bebo will send out a notification if a user is moved to the top of another user's friends list but no notification is sent if they are moved down the list.

This allows users to purge undesirables from their list extremely easily and often without confrontation since a user will rarely notice if one person disappears from their friends list. It also enforces the general positive atmosphere of the website without drawing attention to unpleasant happenings such as friends falling out, rejection and failed relationships.

Investigations

Main article: Use of social network websites in investigations

Social network services are increasingly being used in legal and criminal investigations. Information posted on sites such as MySpace and Facebook has been used by police, probation, and university officials to prosecute users of said sites. In some situations, content posted on MySpace has been used in court.[43]

Facebook is increasingly being used by school administrations and law enforcement agencies as a source of evidence against student users. The site, the number one online destination for college students, allows users to create profile pages with personal details. These pages can be viewed by other registered users from the same school which often include resident assistants and campus police who have signed-up for the service.[44]

Potential for misuse

The relative freedom afforded by social networking services has caused concern regarding the potential of its misuse by individual patrons. In October 2006, a fake Myspace profile created in the name of Josh Evans by Lori Janine Drew led to the suicide of Megan Meier.[45] The event incited global concern regarding the use of social networking services for bullying purposes.

In July 2008, a Briton, Grant Raphael, was ordered to pay a total of GBP £22,000 (about USD $44,000) for libel and breach of privacy. Raphael had posted a fake page on Facebook purporting to be that of a former schoolfriend Matthew Firsht, with whom Raphael had fallen out in 2000. The page falsely claimed that Firsht was homosexual and that he was dishonest.

At the same, genuine use of social networking services has been treated with suspicion on the ground of the services' misuse. In September 2008, the profile of Australian Facebook user Elmo Keep was banned by the site's administrators on the grounds that it violated the site's terms of use. Keep is one of several users of Facebook who were banned from the site on the presumption that their names aren't real, as they bear resemblance the names of characters like Sesame Street's Elmo.[46] The misuse of social networking services has led many to cast doubt over whether any information on these services can in fact be regarded as true.