Niche is good...but some of these sites that cover all niche's have sick amounts of traffic. When you go to some of these sites for one niche...you end up checking out others.
A directory site will do well.
Just be honest in this thread...to succeed just get a tube website, in which will give you traffic. As far as how it converts...have no clue...just testing the Iframe tube feeder with AEBN at the moment.