That's fine, but by then most of the damage has been done. If you visit a website, FB will pick up the cookies from where you've been in that browsing session. While you're on FB it's tracking what ads you're reading. Not just ads, but "Suggested for you" posts. It's tracking how long you spend looking at different posts (especially the paid advertisers). Even if you don't click on one it knows if you paused scrolling for a few seconds to look at it, so it attracted your attention. Whether you're using a mobile device or a PC, it's linking all that stuff with anything else it can glean from that device. How careful are you with what permissions you've given various apps? I'm sure you would be horrified with what these companies already know about you. I'm not just singling out FB here, Google are just as bad possibly worse. If you've got an Android phone you've probably given google the keys to your kingdom. I won't have an Android phone and I won't have Alexa or similar voice assistants in the house.