Fancy joining in with some never-ending collaborative projects? leaveyourmessagehere.com lets you type a random note, but the best bit is reading other people's. Same goes for flickr.com, where you can browse through thousands of photos or add your own.

You can throw your wild ideas for a better world into the ring at halfbakery.com or your slightly more sensible ones to shouldexist.org. Or you could contribute to the brilliant online encyclopedia wikipedia.org, while adding to the Hitchhiker's Guide (bbc.co.uk/h2g2/guide) will help newcomers to planet Earth master everything from the Hangar Lane gyratory system to the offside rule.

Finally,if you want to test the theory that only six people separate you from a complete stranger go to smallworld.columbia.edu - to make friends with them all join online community orkut.com.