By now, it comes as no surprise that Facebook tracks our activity on the website. The things we like, post and share are taken into account and affect what we ultimately see on our news feeds. But on June 12, Facebook revealed that it has tweaked its news feed algorithm to also take into account the time people spend on posts even if they don't take any action. Basically, Facebook knows when you're lurking.

The company said it has made the changes and is in the process of rolling it out based on user feedback. " [J]ust because someone didn’t like, comment or share a story in their News Feed doesn’t mean it wasn’t meaningful to them," it said in a blogpost.

But the modifications aren't as simple as counting the seconds a person spends on a post. Those with slower internet connections will spend more time on stories due to the loading time. So Facebook has a developed a way to look at how much time a post spends on a users screen relative to other posts presented in the user's news feed.

Evidently, Facebook is also able to tell if a person is actively looking at a post on the site, or if it is just open on another tab or window in the background.

Until now, Facebook has only used user's actions to measure engagement. The new method is a much more passive signal to pick up on. This is also a whole new level of invasion of privacy. We had just come to terms with the fact that websites like Facebook and Google were computing our data and actions, now we are forced to deal with the fact that our lurking and stalking tendencies have been caught.

However, there is a counter argument to suggest that it is in fact in our favour that social media sites are computing our data. At the end of the day, they are making the user's experience more efficient and enjoyable. In that sense, how far can they take invasion of privacy before it stops being beneficial to the user and becomes plain wrong?