Uh - Oh!
The idea that advertisers can target people's behaviour on the internet has allowed many companies to become big. The size of the tracking has been increasing in recent months. There are rumours that facebook's new ad announcement on Tuesday will involve a large degree of tracking consumer's behaviour across other sites.
This will definitely rile the privacy advocates, who will be quite disturbed by the idea that facebook's database will be usable across the whole of the internet. The privacy controversy will deter some people from using facebook as much.
It should be interesting to see what evolves from this. Trust is an extremely important thing for social networks - we share a large amount of data with our social network providers. Although many people are willing to share the data with literally everyone, even more people want to limit the data sharing and control where it ends up. How many facebook profiles are shared with everyone?
I don't actually know what the data says but I'd bet that a good proportion are not shared.
I personally believe that facebook is going to come up with a funky way to advertise on their own site. If they do propose an external network model, we'll see some problems arising for many of the other companies that use almost any kind of behavioural targeting.
One quick look at the largest networks reveals many of them collecting large amounts of information on people using cookies. Tacoda (now owned by AOL), Blue Lithium (Yahoo), Adviva and many others will be exposed. Already around 8% of webusers employ some kind of cookie deletion software or some kind of cookie blocker. Increases in this will not make our job any more fun.
Google will remain smugly aloof (at least until they own Doubleclick!) as their model relies entirely on ads relevant to searches, not who the people are.