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Did You Know Facebook Is Probably Tracking Your Sleep Habits? Sleep Tight!

If you weren’t acutely aware of the crushing, silent private- and governmental-surveillance system keeping an eye on us at all times of the day, then how you take this news will depend on your feelings on the relative benevolence of Mark Zuckerberg: Facebook’s ever-expanding data-collection regime is probably tracking your sleep habits. But don’t worry — the data is public, so you can watch your friends sleep, too!

Danish developer Søren Louv-Jansen, used, Facebook’s stand-alone web version of the chat feature, to create a tool that makes rough maps of what his friends’ sleep schedules look like based on the “Active [x] hours ago” data provides. The idea is that since many people check Facebook just before bed and right when they wake up, knowing how long a person has been inactive on the service can give you a good sense of their sleep habits. Simply by going into the markup of, which is publicly available (if not the easiest to find), Louv-Jansen was able to build accurate depictions of what time his Facebook friends went to sleep and woke up.

It’s important to note that it’s not that Facebook is intentionally or specifically tracking your sleeping habits — it’s just that when you combine extensive data collection with a total captive user base, you can build a very accurate picture of a person’s life. (Remember a few years ago, when it came out that Facebook can predict with high accuracy your sexuality, among other things?) The tool only works assuming your friends open Facebook around when they wake up, and stop using it around when they go to sleep — in an interview with the Washington Post, Louv-Jansen said the tool works “extremely well” for 30 percent of his friends, and “somewhat effectively” on the rest. 

Louv-Jansen told the Post that he’d been tinkering with the tool for months, before and after seeing a similar idea posted on Hacker News, but only made the tool available on GitHub in late December and didn’t publicize it until writing a Medium post last week. Facebook, apparently wanting to keep any and all nongovernmental spying over its websites internal, told Louv-Jansen that he was violating its terms of service and to take the tool off of GitHub. He’s refused thus far, telling the Post, “I’m not proud of people starting to spy on their friends, but maybe this can make everybody more aware of the consequences of our actions.” Rest easy!

Facebook Is Tracking Your Sleep Habits