I think it's not to easy. First of a lot of web directories, article directories and forums don't allow to put any adult content and links. Second, it's a great competion on that type of content.
A friend of mine runs a lot of these type of sites and he optimizes some "bait" images for Google and Bing image search. That's how he drives most of his traffic.
I think that it's easy to promote your website, but this promoting activity will be short and you will be upset of its results. So if you have a lot of money and reliable friends you can promote.