A new browser plug-in called Data Selfie lets curious Facebook users “hack” their own data to see what personal information they leave behind when they use the site. The answer, as you might expect, is a lot.

The free tool, which will also be available as an iPhone app when both tools launch in three months, gives users a behind-the-scenes look at how Facebook profiles its users, collecting information from every piece of content we share, comment we leave and post we like. Some of the data the social media giant gathers include your personality traits, sexual orientation, religious views, political beliefs, and much more. This is super creepy, but that’s exactly what Data Selfie is trying to tell users.

“We are under constant surveillance by social media companies and ‘share’ information unconsciously,” the extension’s “About Us” page says. “Therefore, it is important — especially for those who are indifferent to this issue — to be aware of the power and influence your own data has on you.”

It’s eye-opening and kind of frightening to see all of your personal information laid out like that, but the tool makes its point: Facebook knows way more about you might be comfortable with. What you do with that information is up to you, but at least Data Selfie and other tools like it help to shed some light on the issue.