Social notworking site Facebook has just marked its sixth birthday and it still keeps growing like that strange lump on my back.

Founder Mark Zuckerberg claims the site now has 400 million users, which sounds even more impressive if you consider that it had 300 million just 5 months ago.

The company is marking its birthday with a redesign of the site and it's holding some sort of programming competition for its engineers at Palo Alto, which probably wouldn't attract a huge audience if it were televised.