Can Do Exchange
A site where groups or individuals can share their skills and knowledge about anything at all, as well as their equipment and materials.
Londonist
Everything you need to know about London and everything that happens in it. This mecca contains news, reviews, opinions and huge long lists of useful London-related stuff.
Flickr
The ultimate online photo sharing community that’s slowly but surely taking over the world. OK, so we’re a bit biased towards this one, but we just couldn’t stop ourselves from including it in here.