If it feels like the ads chasing you across the internet know you a little too well, it’s because they do (unless you’re an avid user of ad blockers, in which case this is not for you). Earlier this month we announced Enhanced Tracking Protection on by default for new users in our flagship Firefox Quantum browser as a way to stop third-party cookies in their tracks. If you’re still not sure why you’d want to block cookies, today we’re launching a project called Track THIS to help you recognize what they do.

You’re being followed across the web through cookies—small data files stored by your browser—that remember things like language preferences, sites you’ve visited, or what’s in your shopping cart. That might sound generally fine, but it gets shady when data brokers and advertising networks also use cookies to collect information about your internet habits without your consent. You should still have control over what advertisers know about you—if they know anything about you at all—which can be tough when web trackers operate out of sight.

That’s why we made Track THIS: to bring that out-of-sight tracking front and center. Step into someone else’s shoe ads for a while by opening up 100 tabs at once.

Let’s be clear, though. This will show you ads for products you might not be interested in at all, so it’s really just throwing off brands who want to advertise to a very specific type of person. You’ll still be seeing ads. And eventually, if you just use the internet as you typically would day to day, you’ll start seeing ads again that align more closely to your normal browsing habits. If you’d rather straight-up block third-party tracking cookies, go ahead and get Enhanced Tracking Protection in Firefox.

Here’s How Track THIS Works:

WARNING. Before you try Track THIS, get your tabs in order and save your work. Maybe even open up a new window or browser. Track THIS will open A LOT of tabs. 100 tabs is a lot. Choose a profile to trick advertisers into thinking you’re someone else. If you’ve ever wondered what life might be like as an owner of a YouTube tea channel or someone who is actively preparing for the end of the world, this is your chance! The choices are: Hypebeast, Filthy Rich, Doomsday, or Influencer. Confirm that you’re ready to open 100 tabs based on that profile. Close all 100 tabs and open up a new window. Watch your ads across the internet change before your eyes. Your ads will probably only be impacted for a few days, but ad trackers are pretty sophisticated. They could start reflecting your normal browsing habits sooner than that. When you’re done with the experiment, get Firefox with Enhanced Tracking Protection to block third-party tracking cookies by default.

Try it out for yourself here.