How to hail a London cabbie using Twitter

Next time you're in London and need a cab, you might like to try tweeting @tweetalondoncab for one. A small circle of tech-inclined cabbies have spent the last year building up a black cab service on Twitter, and are finding the data the service generates is the really interesting part. By Jemima Kiss

How I became a Foursquare cyberstalker

It's the coolest social networking tool in the world. But is the geo-location app Foursquare a stalker's dream? Just how easy it is to uncover the intimate details of a complete stranger's life?

Hi5 switches to social gaming to take on (bit of) Facebook

It is little known in the UK, but Hi5 is a popular social networking site in the Latino communities of the US, among others. It 72x smaller than Facebook, says Nielsen, but has switched strategies to try and compete. By Jemima Kiss

What’s with the Twitter glitches?

There are more problems at Twitter – users can't update their profiles today and couldn't follow or unfollow people on Sunday. By Jemima Kiss

Can Twitter save the BBC?

After the victory over 6 Music, Twitter campaigners are using the #proudofthebbc hashtag to voice their support for the corporation. By Steve Busfield