buddyping allows your location and those of your friends to be established via your mobile phone (see the map widget in the sidebar. you can send me a text from it if you like!). you can also send photos and buddyping will tag them with geolocation coordinates and you can upload to flickr, which is nice. you can find out where your friends are by pinging them on your phone, which gets more useful when your actual friends decide to sign up. Hint hint. So far, that's all, so it isn't really a serious rival to, say, dodgeball. But it's early days and hey, it's British! That is, it actually works in the UK. Unile dodgeball and the amazing looking socialight. (PLEASE launch in Europe soon!)
twitter let's you tell the world - and your friends - what you are up to at any given moment, and also keep track of what said friends and other twitterers are doing, thinking, etc. Initially I was like 'whatever' but I already find it strangely compelling. You can send or receive updates via your phone, which means that the panopticon can follow you everywhere you go! I know certain people who might find that idea completely appalling (hello dear!) but hey, it's opt in, and it is quite nice to see what your buddies are up to, if for example you are stuck on a boring bus trip or something. Also, the widget (see sidebar, again), means that I now have a sort of mini-blog-within-a-blog which I can update from my phone, whenever I am bored/inspired enough. I think it's very cool. But then, I'm a big geek.