And this one isn’t just limited to Facebook.
Social networking sites may be sharing a lot more of your identifying data with their advertisers than you realize.
From the link:
A report in the Wall Street Journal indicates that a number of social networking sites (including Facebook, MySpace, and Digg) may be sharing users’ personal information with advertisers. Since the Journal started looking into this possible breach of privacy, both Facebook and MySpace have moved to make changes.
The practice is actually a somewhat defensible one–and most of the companies involved did try to defend it–in which the advertisers receive information on the last page viewed before the user clicked on their ad. This is common practice all over the web, and, in most cases, is no issue–advertisers receive information on the last page viewed, which cannot be traced back to the user. In the case of social networking sites, the information on the last page viewed often reveals user names or profile ID numbers that could potentially be used to look up the individuals.
Depending on what those individuals have made public, advertisers can then see anything from hometowns to real names.
The Journal interviewed some of the advertisers who received the data (including Google’s (GOOG) DoubleClick and Yahoo’s (YHOO) Right Media), who said they were unaware of the data and had not used it.
For some reason I find that last claim from DoubleClick and Right Media a bit hard to believe.