Google AdSense has an API that'll let you pass keyword 'suggestions' to it. It's not available to the general public, though. There was some discussion on thi

Google AdSense has an API that'll let you pass keyword 'suggestions' to it. It's not available to the general public, though. There was some discussion on this quite a while ago: http://news.ycombinator.com/item?id=928904 http://news.ycombinator.com/item?id=928904