In my case, my pages are the equivalent of Bob's, they are at the end of the link referral line. Users create content on my site and link to it from their sites. If it were blog or article type content, I would think there's no issue putting ads on the content, but seeing how my site is a web tool/app, it seems like more of a gray area. There's risk I'll piss off my users. I'm trying to decide if it's even worth going down that road.