For an article that completely changed my view on the prudence of an investment in Facebook, see here.
No one can touch that sort of granular marketing. No one.
I dont fully understand that article. How can Facebook use that information to create advertising on other sites if their users arent currently logged in to facebook. On facebook they can use the info from the users input to target ads. But the article says that they will eventually use their info to have targeted ads on other sites and I dont believe that is likely without creating huge legal and privacy issues (much bigger than their current privacy issues). Also, google is able to put together an immense amount of info about their users based off of searches and web sites visited thru google.
One huge advantage that google has with its adsense is that when people are using google they are often looking for products and things. Advertising works because it gives them what they are looking for. However, when people are on facebook or other similar sites they have less interest in the ads, the ads just get in the way of their "socializing." Google and its purpose is just inherently built for advertising to work in a way that no other model ever has.
I hear why you think that facebook has a strong future and I dont disagree with that, but there is no way that google fears facebook. Now if google was able to find a way for google+ to really take off then facebook would have what to be afraid of (I doubt this will happen).