I played about a week or two with a friend, a MW2 match, private match. He was on my Hamachi network, since then he is on my friends list in game. The question is, how did he get there, and, can I add another friend? He wasn't the only one in my Hamachi network, there was another friend of mine, that played the same private match with us, and he didn't get on my friends list.

The friendslist comes from your Steam friends.

Oh, thanks!