Tumblr is great. I encourage all of my affiliates to use it. To me, it is the perfect blend of social and porn. Each tumblr theme (the paid ones, at least) are highly customizable. It is possible to run any ads you want. They are fully aware that tumblr is primarily run by pornography.
On a side note; has anyone ever read their TOS? It's the most hilarious I've read in a while. They even plug xhamster WITH a direct hardlink!
