I just posted this comment at SIA regarding Tumblr's claim of 625,000 users.
I thought it was worth posting the comment here as well.
Yep, i dont see the business model.
It's easy to build a free service for 625,000 users.....converting them to paying customers is hard.
Want to see how easy, give me 625,000 Mars bars and I'm sure i could get rid of them in under a day at Union Square park on 14th St.
Whats the point.....?