My personal favorites are the anonymous internet tough guys: "if I ever met him in person, I'd punch him". No, you wouldn't. You'd walk on by in silence, thinking your snarky little thoughts and tell your friends about it later. Because you, sir, have likely never been the first to throw a punch in your entire life.
I'm not saying one is wrong in feeling a little sting in such comments. Maybe it's too many years on Usenet, maybe it's spending way too much time on Xbox Live (that will grow you a thick skin), but I just pay them no heed anymore and let them wallow in their insecurity.
That's not to say that when my mother is referenced on Xbox Live that I don't point out that the 68 year old woman would probably love some time with a young, studly Call of Duty master like yourself.