Now at 50 million blogs: http://www.businessinsider.com/the-story-of-tumblrs-impressive-growth-2012-3

They just passed 20 billion posts: http://thenextweb.com/socialmedia/2012/03/28/tumblr-hits-20-billion-posts-nears-50-billion-hosted-blogs/

Which is amazing considering they passed 10 billion posts six months ago.

Those are some impressive stats. Do you have any figures on average number of followers per blog?

I can never seem to get as many followers as I would like...

Source: rosiedoll.tumblr.com

According to the reliable source penis police...

there are over 50 million tumblr users

an average user has about 108 followers

49,999,892 people don’t follow you

how does that make you feel?

I think that although the average might very well be 108, that's skewed by a few celebrity and brand Tumblr blogs that have more than 100k followers.

I also found how many followers the top 15 Tumblr blogs have.