The next time you share a link with a Facebook friend via private message, be aware that you're anonymously "liking" that page publicly as well.
That’s what developers with Polish startup Killswitch.me discovered while researching other issues surrounding the “like” button. They stumbled upon the fact that sending a message to a friend with a likable link triggers an anonymous like of that page.
While this may come as a surprise, evidence that the company was scanning our messages for these likable links has been public for at least a week. Facebook states in a September 27 FAQ for developers that “the number of inbox messages containing this URL as an attachment” is a factor in counting the number of likes that shows up on a page’s Like Button.
Other factors include the number of actual likes, the number of shares (including a share on Facebook), and the number of likes and comments on stories on Facebook about the URL.
While this information seems to have been public for some time, those of us who aren’t developers likely had no clue of Facebook’s actions. That said, given how Facebook uses our activities to further its own business interests, this practice shouldn’t surprise us. Facebook routinely relies on its members' personal information when it comes to serving more targeted ads.
Personal messages seem to be another matter, however. We may privately share something with a friend that we’d rather not make public. Facebook seems to acknowledge that, assuring The Next Web that the mention of the link merely adds an anonymous "like" and that no page or link is automatically liked on the user’s behalf, nor does it appear on a user’s timeline.
Will this appease privacy critics and uneasy users? As long as this remains Facebook's policy, it should. But Facebook should be warned: a recent study by researchers at New Jersey Institute of Technology and Pace University shows that users are paying attention, and will respond if they feel their privacy is threatened.
Compared with Facebook users five years ago, today’s Facebookers are much more engaged in protecting their privacy, and more “proactive” when it comes to responding to incidents that may affect their privacy on the site, researchers say.