If you’re getting targeted with surprisingly relevant ads, there’s a chance your internet activity is being tracked and analyzed by market researchers. While this doesn’t bother most people, private browsing mode can offer you some protection against online marketers and would-be data thieves.

If you’re disturbed by advertisements and “helpful” suggestions that are based on your internet browsing habits, recent research has found yet another source of online tracking. It’s a sneaky tactic that also comes with serious security concerns.