I really wish I could pay for free services just for the peace of mind that they'll stick around.

I've got my website on Tumblr and by using their service I feel like I'm making a pretty big commitment to them, but since it's free it doesn't feel like they have the same level of commitment to me.

I freaking love Tumblr and would be happy to pay. But right now it's not clear to me if they're making any money at all and that's a big concern as a user. Just remind me, how do those guys make money again?

Also, Pinboard founder Maciej Ceglowski wrote on the topic of being a free user not that long ago: http://blog.pinboard.in/2011/12/don_t_be_a_free_user/

The TL;DR version was: Exploding growth + free service = losing lots of money. Ouch.