Do any social networks target ads based on user profiles?

[Flibble]

Just a quick question which is intreiging me! (apologies if wrong forum...)

Do any social networks target ads based on user profiles?

My sense is that Facebook does not, however would it not be a fairly simple bit of coding to link up the two?

Would allow CPM to perhaps double, or triple... As truly targeted...

Thanks!

[Beagle]

If they don't, they could look at amazon's omikaze ads, which do a similar thing. The direct product links I choose myself do better in sales, but on less-targeted pages I've sold some unexpected things through the omikaze ads (belly dancing videos on a literary site?). AFAIK, all amazon has to go on is the user's amazon history, not everything she or he does on the web.