How Twitter Works

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.

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.

In the beginning, Tweets were text only. Now, Tweets can include pictures, as well as six-second video clips (courtesy of Vine, which Twitter purchased in 2012).

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.

You don't have to generate original content in order to send Tweets. You can simply share the Tweets that other people create, in effect forwarding their message all of your followers. This is calling Retweeting.

As a way of categorizing and grouping messages, many users use the hash symbol followed by the Tweet's subject. For example, if you're Tweeting about your new car, you might include #newcar #porsche #bankaccountempty as part of your message. These hashtags make your message more searchable for other users.

In the next section, we'll learn about Twitter's many applications.

Twitter bases its application programming interface (API) off the RepresentationalStateTransfer (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.

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:

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

In the next section, we'll look at technical side of Twitter -- how it interfaces with mobile devices.

Twitter was always meant for mobile, so the vast majority of Tweets originate from mobile devices. Meanwhile, the number of Tweets from desktop computers is consistently falling [source: Madrigal].

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.

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.

Twitter has overrun the world with Tweets. According to the company, people send more than 500 million Tweets per day. That's nearly 6,000 Tweets per second [source: Krikorian ]. The average active user Tweets about 20 times per month, although nearly a third of accounts are inactive [source: Madrigal]. Still, there are about 560 million active accounts, and about 241 million of those post every month [source: Smith].

People who use Twitter frequently spend about three hours on the service per month. About half of those people access their accounts once per day [source: Smith]. What all these numbers means is that in terms of social media and information proliferation, Twitter matters.

When major news events occur, Twitter knows. After the announcement of Michael Jackson's death, Tweets mentioning the singer topped out at about 220,000 per hour and at one point crashed the system entirely, making it inaccessible to anyone [source: Shiels].

At the 2014 Oscars, Ellen Degeneres captured a selfie with a group of other celebrities. Within an hour, her Tweet had been re-Tweeted more than 1.3 million times, which set the record for the highest number of re-Tweets from a single post [source: Gerick].

Indeed, the most popular subjects on Twitter are a reflection of the human hive mind at any given moment. These trends are easy to spot -- they're located in the Trends box on your Twitter homepage. So when pop culture sources or news media proclaims that a topic is trending on Twitter, you can bet that the subject is far-reaching or at least weird enough to grab worldwide attention for a few hours.

Twitter is continually evolving. Its programmers make it more user friendly by continually refining the search engine. And they refresh superficial visual elements from time to time in order to maintain a modern look that appeals to people who also enjoy image-laden social media services like Facebook.

Although Twitter started in the United States, only about one-third of Tweets originate from North America. English is the by far the most dominant language in Tweets, and Japanese and Spanish come in at a distant second and third, respectively [source: Richter].

With hundreds of millions of Tweets appearing each day, it's clear that the power and influence of Twitter is real. When the Arab Spring took hold in the Middle East in late 2010, many revolutionaries turned to Twitter to organize marches and protests, and to warn each other of danger from the authorities.

For serious political purposes, or for pointless chatter, Twitter's casual nature can be both a blessing and a curse. Tweets are an easy, fast way to communicate ... but mindless comments can go viral in a bad way.

As Exhibit A, let us revisit the firestorm sparked by Justine Sacco, who was the head of corporate communications at a media company called IAC. Sacco was heading to South Africa for a vacation when she brainlessly Tweeted the following: "Going to Africa. Hope I don't get AIDS. Just kidding. I'm white!"

A few people saw the Tweet and shared it. Before her plane had even arrived in South Africa, Sacco's name became associated with racist-tinged ignorance. She was fired from her job and instantly found an infamous place in Internet lore.

Popular cable satire show "The Colbert Report" experienced Twitter-based backlash as well. After a staffer posted a satirical joke about racism out of context, an angry Twitter user called for the show's cancellation. Soon, the hashtag #cancelcolbert was trending on Twitter.

Colbert's writers defused the uproar with a long segment on the situation, in part mocking Twitter itself. Colbert capped off the segment by saying, "Who would have thought that a means of communication limited to 140 characters would ever create misunderstandings?"

Businesses are all too aware of just how fast Tweets go viral. Consumers who post complaints may see their words echoed by many others, resulting in public relations disaster for an organization. That's why many companies employ people who monitor Twitter and other social media sites, ready to address gripes before they make headlines.

The same goes for politicians. When British politician (and Twitter novice) Ed Balls accidentally Tweeted his own name, the Internet, of course, was quick to pounce and make a mockery of him. Now, each April 28 people in England have a tongue-in-cheek celebration "Ed Balls Day."

Twitter has cemented its status as an innovative communication tool. In just the few minutes it took you to read this article, thousands of new Tweets appeared, all adding to the chronicles of human history, 140 characters at a time.