I don’t have a Facebook account, and when someone sends me a link to something on Facebook, I get a GIANT pop-up covering the entire screen which tells me to login or create an account. If I click “remind me later” (there’s no way to close or move it otherwise) it minimizes to cover just the lower ⅓rd of the screen. No one has yet found any way to stop it as far as I know, even on the AdBlock forums, because it seems to randomize filenames and script names and stylesheet names specifically to prevent people from blocking it. It also institutes a small delay in firing off, again to thwart attempts to block it on page load.
I never willingly visit Facebook, but sometimes I get sent there from a redirect URL, and every time it happens it reminds me why I refuse to accept Zuckerberg’s Mark of the Beast.