URL shorteners were thought to have lived their heyday earlier this year when every other startup was in the link shortening business. After a while though, it became clear that there was simply no space for all of them and with no_url_shorteners the unchallenged leader in the market things looked settled. Last week though, things changed dramatically as both Google and Facebook entered onto the scene with their own take on URL shorteners. And it's not over yet, YouTube has also come up with its own shortener, and this one too is slightly different than the others.