Real-time micro-blogging is gaining in popularity. But if you're wondering what's the point, here's Charles Arthur 's guide to the benefits of Twitter - and how to get started

An American student is arrested in Egypt, and manages to send a brief text with a single word - "ARRESTED" - which is picked up around the world, and leads quickly to his release, helped by a lawyer hired by his university back in the US. In Britain, the prime minister's office decides people should be able to find out what their premier is doing; as of today, more than 2,000 people do. During an interview at the SXSW festival in March, audience dissatisfaction with Sarah Lacy's interviewing style with Facebook founder Mark Zuckerberg spills over into silent but powerful discourse among the audience: one calls it a "train wreck". People fleeing from fires in California say where they are; that proves more useful and timely than official goverment information.

The common factor? Twitter, the free (at present) service which lets you send a 140-character message, or "tweet", to a site where anyone can read it, though it will only be sent directly to those who have chosen to "follow" you (though if you want, you can pick and choose who you allow to follow you). Twitter's first prototype was built in two weeks in March 2006 and launched publicly that August. It has only been a company since May 2007, but its growth has been explosive - so much so that it constantly struggles to keep running as a growing number of people sign on, sending more and more tweets.

One of the first questions people ask is "what is Twitter for?" As with any social network, the answer is the same: whatever you make of it. Some think that its immediacy makes it ideal for spreading news. Others find it useful to ask questions of their peers; still others, for following what people or topics they're interested in. The BBC and the Guardian, for example, already offer Twitter services for breaking news (check out the Guardian Technology Twitter feed). It will be surprising if IBM does not offer a Twitter service with results from the All-England Tennis Club Championships in July.

Hitwise, the web measurement company, notes that traffic to Twitter has risen eightfold in the past year, more than doubled in the past three months and up 60% in the past month. By Hitwise's measure, it's only ranked 439th in social networks - outside the mainstream - but Heather Hopkins, senior Hitwise analyst, adds quickly that: "Twitter's size is notoriously difficult to measure as there are so many access points (mobile phones in particular)."

That is a key point. Measurement companies like Hitwise tend to rely on browser-based metrics to see where samples of people are going. But whereas Facebook, MySpace, Bebo and Habbo Hotel are only usable through a web browser, Twitter has broken free of the web; its text message-length "tweets" can be received on a mobile phone or other device. You don't have to visit the web page to use Twitter; in fact, doing so may be one of the slowest ways of using the service. And many of the systems that are built around Twitter use web pages to interface directly to its database (via a published API). Twitter didn't respond to a request asking how many active users and how many tweets are sent each day; but it's a safe guess that both are in the millions. TwitDir, a Twitter directory, suggests there are now 1.05 million Twitter users - up from 518,000 in October.

With Twitter thus poised to enter the mainstream, we offer here our list of the best tools presently available on, and built on, Twitter. As ever, this is a moving target: within months we expect there will be even better ones. And we will watch our Twitter feeds for your responses and suggestions.

First steps



Twitter.com obviously. You don't need to sign up; you can watch the flow of messages from a particular user at their username (eg Guardian Technology's, which is at twitter.com/guardiantech). However, Twitter only becomes useful once you can sift through the huge volume of posts. Signing up is free and you're not obliged to follow anyone, or post anything, or let anyone follow you.

Next steps

You can follow Twitter at the website, but that's inefficient. Smartest moves: get a program for your PC, Mac or Linux box to watch the flow.

Windows

Madtwitter; Twitteroo; Twitterlicious

Mac OS X

Twitteriffic

Linux

Deskbar; Twitux

Mobile phones

Twittter for iPhone; Twitterberry (for BlackBerries); hahlo.com (iPhone and others)

Firefox

Tweetbar

Finding people

Whoshouldifollow.com answers that simple question. Given your username, it will look for other users with some overlap with the people you follow, and suggest them as people for you to follow. Add some of the names there and then repeat the process, and you'll quickly build up a large network.

Twitdir.com, a directory. Find people, and quickly see the top 100 most-followed and busiest twitterers.

Twitterholic.com, the top users and accounts: choose, then repeat as above.

Searching and organising

Summize.com, search for a word or phrase across the entire Twitter feed. Interested in Scotland? Explosions? Burma? Plug the search in and view the results; or take an RSS feed, which will automatically update when new tweets match your search.

Quotably.com creates threads of discussions between people.



Terraminds.com, another search engine, for users or phrases.



Tweetscan.com, search by user and time.

Twitterlocal.net finds twitterers near you.

Sharing

Twitthis.com, lets people looking at your site or blog share the URL via Twitter.

Twitturly.com, what's being most linked-to and talked about?

Tweetmeme.com, what sort of topics are being discussed?

Visualise

Twittervision.com, real-time Google Maps mashup showing where the latest tweets are being posted.

Twitterverse, tag clouds based on the messages flowing through twitter.

Twistori.com, love, hate, think, believe, feel, wish: what people are saying where the tweets use those words.

Twittearth.com, processor-heavy, but fascinating, visualisation of tweets, put onto a spiralling globe.

Tweetwheel.com, which of your friends are already following each other?

Miscellaneous

Tweetspeech, Yahoo Pipes module that converts (incoming) tweets to speech, playable via RSS.

Tweeterboard, a "leaderboard" of who the busiest, most popular, most chatty users are.

Twitter fan wiki, lots more Twitter information and applications.

Twittersnooze.com, hit the "snooze button", briefly, on verbose friends.

Twitter balloon, your tweets superimposed on an image of your choosing.

Latest Scores, latest football scores, as tweets.

twerpscan.com, avoid followers who befriend everyone: may be spammers.