- Your site does not work with Javascript turned off. If you're trying to get the small towns and such, you need to be careful on this.
- At first entrance of your site, it looks like a typical domain parked page with some ads. Make it more clear your site is about small towns and neighbourhoods. Display your top cities up front, or at the very least use some simple ip location to grab where I am and display relevant content.
- You want to make me register to contact someone. Not going to happen
- All the AJAX you are using is totally unnecessary.
- Stop calling yourself a Craigslist killer and focus on a single niche, in a few small towns and do it well. Dominate those towns and that niche, then expand.
That, along with everyone elses comments should start you off .. good luck