"Like" being spied on by Facebook?

The ulterior motives of the seemingly harmless social network sharing buttons which now appear on thousands of top websites.

Cookies, and not the edible kind, are now being placed on a user’s computer after visiting websites containing a Facebook Like button or any other social network sharing button, such as the Tweet button. Primary intent of these buttons is meant to allow users to share interests and other favored items with friends through their social network’s news feed. Evidently, this is not the only purpose they serve.

Even if a web page visitor doesn’t actively click on the button, personal information and browsing history can be linked to the user and their personal profile, provided they have logged into their social networking page within the last month.

It is estimated that Facebook buttons now appear on one-third of the top visited websites, with Google buttons following close behind. Google buttons are used similarly to social networking buttons and can be found on approximately one-fourth of these sites. The use of the “Tweet” button for Twitter is also on the rise, currently seen on one-fifth of top pages.

According to creators of the Facebook button, information gained from user activity tracking is used only to create powerful, highly targeted advertising on the site. They claim that personal data is made anonymous and the data cannot be tracked back to specific users. However, the data collected remains in the system for three months, much longer than Google’s two week info-retainment period.

If you are concerned for your social networking confidentiality, Kashmir Hill of Forbes suggests you “log out of these sites after you’re done checking your email, tweeting, poking or what have you.” But most Facebook users may find the privacy risk is preferable to frequent logins.