My advice is if you can't do it yourself, you're going to end up paying a LOT of money for development -- like multiple tens of thousands of dollars -- before you even go live, with no guarantee that the quality of work will match your vision. It's a tremendous risk. (that's for a social media web app of similar size and scope as Pinside .. although not remotely as polished and fully-featured. A site like this takes YEARS of dedicated development)
I've spent hundreds of hours doing all my own development for iScored. And the thing is, it's a really simple concept. In fact, I had a working prototype done in one mad night of coding when I first got the idea about 4 months ago. But that was just barely the tip of the iceberg. The sheer number of things that had to get done to make it a workable product I was comfortable charging money for just grew and grew ... and grew. And then when I started showing it to people, new things I didn't know I needed became necessities as well. The project wouldn't have been remotely viable if I had been paying someone to do it even at entry-level coding wages. (and do you really want entry-level work anyway if you're spending all that money?)
Maybe I'm wrong. Maybe there's a team out there that will implement exactly what you want for a good price. And if so, I hope you find them. Cheers and good luck.