Is Facebook on a collision course with privacy watchdogs? There have been isolated complaints in the U.S. and in Europe to rein in the rapidly growing social network and how it handles user data, but so far regulators have remained on the sidelines. That could change with a new feature Facebook is due to introduce later this week at its F8 conference.

Marketers are telling the Financial Times that changes in store for the 400-million-strong social network include turning the “Become a Fan” button underneath various content offerings to “Like.” (That much we already knew). The new bit is that the new “Like” content-sharing feature will enable marketers to see what users are responding favorably to, for purposes of targeting them down the line with an ad.

Facebook isn’t saying much at the moment, waiting instead for Wednesday to unveil the full details. Mashable explains though that this new social media marketing feature shouldn’t be too prickly for users, saying:

Facebook already targets ads using information from your profile, and this new system will not track all of your browsing… Rather, Facebook will offer sharing buttons to interested websites. Readers will be able to click on them to share the links with their Facebook friends via Facebook Connect

By extending Facebook connectivity outside the network, marketers will be able to see how people are interacting with their content and then respond accordingly with a targeted ad. What’s not to like about that?, most marketers are no doubt thinking.