Yeah, well that happened to me today. Twice.
To be fair, one of the people who added me, I didn't send a request to. They just added me and then I was asked if I wanted to add them back. And I said to myself "self, this person hates your guts. I have no idea why they added you, but you can bet your bottom dollar that as soon as you add them back they are going to drop you." I said this to myself and yet I added them back anyway. I'm such a sucker.
The other one, though, accepted my friend request and I have no clue who they are. I think they might be a blogger, but we have no friends in common and I don't see any links to their blog on their page, so I have nothing to go on.
Hey, maybe I'm just THAT popular?