So I was on another website (reddit.com) recently and someone had asked a programming question in one of the forums there. I quickly found an answer on this site (stackoverflow.com) and posted a link to the question as a reply.
A couple of hours later I logged-in to stackoverflow again and was notified that I had received the 'Announcer' badge. The 'Announcer' badge basically says that if you post a link on another website and it is viewed 25 times you get the badge.
My question is: How did Stackoverflow know that I posted the link on another website and how did it link the 25 clicks by other users to me?