There has been a lot of buzz around Tumblr recently, mostly thanks to Yahoo!'s $1.1 billion acquisition of the company a few weeks ago. There's almost no doubt that the microblogging network's price tag was worth it. There's no avoiding the obvious: Tumblr's huge, and it's only going to get bigger. But, what's happened behind the scenes; how did Tumblr and its founder, David Karp, get to this point? Here are 30 things you didn't know about your favorite microblogging service. Now tumble that.