I'm currently running a community based website that focuses on Bartering and Exchanging goods and services between people without involving money at any point. While I have a a decent sized community (just over a 1000 users scattered around different areas of the US), I seem to only be getting new users at a very slow pace. My site has only a couple public facing pages, the majority of the pages are password protected, so SEO has been difficult to implement. I do have a Facebook page, and I did run a FB ad which brought in more likes to the FB page, but not the site. I've also tried reaching out to different groups with bartering as a theme, but have had very limited success.

I'm wondering, how did Yelp and Angie's List and other different types of niche community based websites build up their user base?

Any advice would be greatly appreciated!

Cheers Josh