Twitter is a free messaging and micro-blogging service – think of a combination of a blog, a messaging service, and a social network. See www.twitter.com for more info. More people all the time are joining Twitter to take advantage of quick, informal messages, the exchange of ideas and links, or maybe just daft comments about what’s going on in the news.

The idea is simple – you post a message, people can reply, and you can reply to other messages. If you like someone’s style you can ‘follow’ them to see what they have to say, and they may even follow you back. If it all sounds a bit unfamiliar, or you think email and the like is quite enough, don’t worry – it’s easy to give it a go, and you might even enjoy it.

Below are some notable Twitterers – to follow them or see what they have to say, just click the links:

• Stephen Fry (British National Treasure)
• John Cleese (Python and mustard fan)
• Al Gore (erstwhile President of the USA and environmental campaigner)
• PZ Meyers (author of the Pharyngula blog)
• Penn Jillette (presenter of the ‘Bullshit’ TV series and half of Penn and Teller)
• Robert Llewellyn (‘Kryten’ in Red Dwarf and presenter of Scrapheap Challenge)
• Phil Plait (astronomer and skeptic)
• Mars Phoenix (the Mars Phoenix Rover)
• Darth Vader (Sith Lord)
• The Atheist Bus Campaign
• The Flying Spaghetti Monster

And feel free to follow me!