Social widgets, such as the now-ubiquitous Facebook “Like” button and Twitter “Tweet” button, offer users a convenient way to share online content with their friends and followers.
These widgets have recently come under scrutiny for their privacy implications. Yesterday, The Wall Street Journal reported that Facebook, Twitter, and Google are informed each time a user visits a webpage that contains one of the respective company’s widgets:
Internet users tap Facebook Inc.’s “Like” and Twitter Inc.’s “Tweet” buttons to share content with friends. But these tools also let their makers collect data about the websites people are visiting. These so-called social widgets, which appear atop stories on news sites or alongside products on retail sites, notify Facebook and Twitter that a person visited those sites even when users don’t click on the buttons, according to a study done for The Wall Street Journal.
It wasn’t exactly a secret that social widgets “phone home.” However, the Journal’s story shed new light on how the firms that offer social widgets handle the data they glean regarding user browsing habits. Facebook and Google reportedly store this data for a limited period of time — two weeks and 90 days, respectively — and, importantly, the data isn’t recorded in a way that can be tied back to a user (unless, of course, the user affirmatively decides to “like” a webpage). Twitter reportedly records browsing data as well, but deletes it “quickly.”
Assuming the companies effectively anonymize the data they glean from their social widgets, privacy-conscious users have little reason to worry. I’m not aware of any evidence that social widget data has been misused or breached. However, as Pete Warden reminded us in an informative O’Reilly Radar essay posted earlier this week, anonymizing data is harder than it sounds, and supposedly “anonymous” data sets have been successfully de-anonymized on several occasions. (For more on the de-anonymization of data sets, see Arvind Narayanan and Vitaly Shmatikov’s 2008 research paper on the topic).



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