I have a couple of FB accounts. All work well. Now I wanted to add a new account. So this is what I did: 1. Got a private proxy that is dedicated to this account. 2. Set up a different browser with this proxy (Firefox & proxy), dedicated to this account. 3. Disabled Flash on this Firefox browser, to make sure the real IP doesn't leak. 4. Used this browser & proxy to open the new account. 5. Got a phone number to phone verify the account. 6. All my other accounts are only used on a different browser (chrome), with a different IP, on the same pc. So there shouldn't be any way for FB to tell that this new account is somehow connected to my other accounts. And guess what: It works, but on the "people you may know" list, FB shows me people that are my friends on the OTHER accounts. So obviously FB can tell that the accounts are running on the same pc or can somehow detect that the proxy is hiding the real IP. But How? The only idea I have is the cookies on this pc, which I DON'T delete. I've read different opinions regarding the cookies. Some say to delete the cookies, but others say to keep them, so that even if you do switch IPs, FB won't block your account (thinking that someone is trying to hack it) as they'll know it's on a pc you've used before. Any other ideas how they can tell?