I've been posting stuff on YouTube since late 2007 - 240 in all - and I've only ever had a handful of weird/abusive comments. If people genuinely don't like what I play, then I have no problem with that - though i personally never post negative comments on other people's videos. If I don't like them, I pass on in silence.

My strategy for dealing with the few abusive ones - typically, two young teenagers giving me the finger in video and calling me an old turd (sad, eh?) - is simple:

(1) I go to the commenter's channel and block them

(2) I then remove the comment

End of story.

I also use this where a comment is actually a sly ad for some other band or for software.

The weird or odd comments - like being propositioned by young, bearded men ("Will you be my Daddy Bear?") - I just laugh at and ignore. On the other hand, I always respond to requests for hints or tips or tablature, if I can.