I tend to recognize people if they have a unique avatar, especially if it's something that stands out to me personally like a character or game that I like.
Even then, I just recognize the avatar and not the name. Chances are I wont remember anything about where I saw the person, what they said, or anything about them beyond the avatar.
I don't post much but think I have a fairly distinct avatar and when I do post I usually end up going back an forth in a debate with people for quite a while, so it's possible they remember me. Beyond that, I doubt it.