Ask HN: How to find market/industry data?

Hey all,

I'm looking to find some market/industry statistics to build the story around my venture. I have a lot of anecdotal evidence (personally and through conversations with individuals) to support my story, but I know hard data is king.

I'm looking for info related to the social network and online dating markets. Where are some good places to look for this kind of stuff? I'm not looking to pay for it.

Any alternative methods or techniques for estimating or finding this sort of data (especially if used by you in the past) would be helpful.

thanks!