1. Pinterest
Back in 2008, Google estimated there were around 1 trillion unique URLs on the web (which isn't quite the same as 1 trillion pages – but it's still a pretty mammoth figure). Four years on, no one's produced up-to-date research to find out how big the web is now; but it's safe to say it's pretty damn huge.
'Self-expression engine' Pinterestis helping its millions of users to categorise, comment on and share the web's potentially infinite content, via their desktop site and mobile app.
Pinterest is a virtual pinboard. Pinterest allows you to organize and share all the beautiful things you find on the web. You can browse pinboards created by other people to discover new things and get inspiration from people who share your interests.
When a user 'pins' a piece of content, it is shared with the user's followers who can comment, 'like' or 'repin'(/ reblog) on the pin. The pinned content can also link back to where the user first saw it on the web.
Although the site is still in invite-only closed beta, Pinterest recently hit 10 million unique monthly users, has raised just under $40m in funding and currently drives more referral traffic than Google , LinkedIn and YouTube combined. Pretty amazing stuff!
Until Pinterest launches publicly, you can request an invite from the site – or simply follow Pinterest on Facebook, Twitter or Tumblr.