Facebook friends that show on your friends list a lot, view your profile a lot?

[Person]

The reason why I am asking is because there is this person who keeps showing up. Every single time! I read somewhere that supposedly the friends on your list are people who you recently interacted with.I personally don't know the person, I have talked to that person before, but online via E-mailing and so I would feel horrible if I were to delete him. But, its so creepy because I have never liked, commented, send a message,never have chatted on the IM, or anything! I also never go on that person's profile. I check my Facebook almost everyday and its been about 3 months since I noticed that person there and every time I check it, that person is there. I just want to know because I am really creeped out by this person.