I might be misunderstanding how Facebook advertising works, so correct me if I'm wrong, but from my work with it I understand it to work as follows:

I (a Facebook user) have likes, I have interactions with things (pages, people, websites) and I have personal information (age, gender). An advertiser can target these things (eg: 21 year old male) but they cannot say "Give me the profile URLs of every that likes Minecraft" can they?

For example I currently have this advert displaying on Facebook: http://i.imgur.com/3p9oy.png, Thinkgeek don't know who I am, only Facebook does. Thinkgeek provide the targeting information, Facebook execute it.

If this is the case, how would a company like Thinkgeek ever know to message me about Minecraft things? unless Facebook provided them with my profile, which they do not. The only way to do it would be if they were scraping profiles, which Facebook do not allow and if Facebook were to allow it they would build out such a system (targeted messages).