How does Facebook really identify requests?
Today I have discovered something very strange. It seems like Facebook is playing some kind of unfair game for identifying one's online identity. So, here is what I have done: I have a regular Facebook account, everything is OK. It becomes interesting when I try to create another one using a Proxy running on a virtual machine with different MAC address (even though it is not broadcast) and everything. With that configuration Facebook is able to recognize me and prompts identity check(as I'm creating "Fake" account). They are so good at identifying me that my real profile is shown as recommended friends.
How is this even possible since the only thing they get is a HTTP/S request originating from unknown IP, that the "real" profile never used? What information about my machine is sent to their server?
PS: This is for informational purpose only, I am making my research and conclusions. No funny business!
