When I started using facebook to get people to do CPA offers the problem I had was fb making my links go to a warning page saying that it was a malicious or spam site they were about to visit. This ruins conversions. So the trick I figured out is two steps. First shorten your url using bit.ly and then head over to the tk registrar and register a new domain and set it to forward and link the tk site on facebook. There ya go! Itll let them click your link and the redirect will get past that conversion ruining warning page.