First message posted on Twitter

A new messaging service called Twitter has been created by a small team in San Francisco, allowing people to send short updates about what they are doing to groups of friends.

The first message was posted on 21 March by Jack Dorsey, one of the service's creators. It read simply: "just setting up my twttr".

Short messages

Twitter was developed at Odeo, a company that makes podcasting software, by a team including Dorsey, Evan Williams, Biz Stone and Noah Glass. The idea is to let people share brief status updates, which their friends can receive on the web or as text messages on their mobile phones.

Messages are limited to 140 characters, so that they fit within the length of a text message with room for the user's name. The service is being tested among the company's staff before being opened to the public later this year.

Why it matters

Twitter is part of a new wave of websites and services that let people share information about their lives. Blogging has become hugely popular, and social networks such as MySpace have attracted millions of users.

The creators of Twitter believe that many people want a quicker, simpler way of keeping in touch than writing a blog or updating a profile. By sending short messages, users can tell their friends where they are, what they are doing or what they are thinking.

The mobile connection

Because it works through text messages, Twitter can be used on almost any mobile phone, not just those with internet access. This could make it useful for keeping people in touch when they are away from their computers.

Some people are sceptical. They question why anyone would want to know what their friends are having for lunch, and whether the service will attract enough users to survive.

An uncertain future

Odeo's main business, podcasting, is facing tough competition, and the company is looking for new ideas. Twitter began as an experiment, and it is not yet clear how it could make money.

But its creators are enthusiastic about its potential, and say that the simple idea of sharing short updates with friends could prove popular.

The service is due to be launched to the public in the summer.