[latchkey]

I've got a bit of experience in this area.

I built an ad engine for Kink.com (NSFW) which had ads placed on even higher traffic sites like PH. I built the original pixel tracker for Marin Software, and @stickfigure and I built GearLaunch, which was the backend that sold those t-shirts you're talking about.

Needless to say, you don't see as many t-shirt ads any more because FB cracked down on it... not because of the targeted ads, but because it became a copyright infringement game and it was easy to block the people creating the ads (and shirts) as they were all outside of the US (ie: Vietnam). That and thankfully FB didn't want their wall to be all ads for t-shirts, lol.