It's our second time to help an adult site to marketing. It's a tube site, mainly use other site's video. The last time is an adult image hosting site and attract mainly Chinese, then traffic burst and low income lead to the site closed. It seems not easy to have USA adult traffic so far after few weeks efforts. We are thinking to do some forum postings and link building, seems not easy. CANSPAM newsletters may blacklist our server, bad idea. Buy ad space from some big adult sites? the price seems not pretty high. Is there any low cost ways to promote an adult tube site? here is the new adult tube site.
You can buy ad space that isn't too outrageous. Try bidding for traffic at trafficshop or juicyads. Also I would recommend some social media sites. Twitter is great for this. You can share images and link back to the tube. It's fairly low cost and will build a solid following for you. Also, you may want to pick some better ads for your site. If you have a lot of US traffic you should try BaDoinkCash.com. The payouts are $25PPS or 60% rev share and english speaking traffic does best. Anyway, let me know if you have more questions!