Once you start paying for targeted facebook ads, it seems they withhold you from being seen until you pay again. I paid 5-10.00 here and there with targeted ads, seems I picked up one or two backers, but hard to say because in the stats I have a lot of traffic from facebook, but not sure how to break it down to those I direct messaged in FB vs ads, vs them finding my FB page. I do know a few people that have huge FB lists and they say now only 3-5% of their followers see their posts.
Read this -
https://www.youtube.com/watch?v=oVfHeWTKjag and look for other articles about FB likes.
What I do like about FB is keep posting different uses, visuals that I can refer people to. You HAVE to have a presence on there.