Then what was the comment I made?
You actually wrote the words, "No comment." To really provide "no comment" you wouldn't have said anything at all. Instead, you felt the need to post the words "no comment" which are a comment in themselves. Taken at face value they say you've chosen, for whatever reason, to refrain from comment on someone's actions or statements. Delving deeper, the phrase could be taken as self-depreciating:
joobz: RobRoy, you're an ass!
RobRoy: No comment!
A commentary on a statement you feel is beneath you:
RobRoy: . . . and then, the fluffy pink bunny rabbit picked me up, and let me ride on his back all the way to La-La land where there was milk, and honey, and chocolate, and those marshmallow chicks, and . . .
joobz: No comment!
Or it could be a sarcastic statement, after someone has said something you find particularly silly or unworthy of addressing:
RobRoy: Huphlelumps!
joobz: No comment.
And that's just scratching the surface! You clearly wanted some kind of response, either from me, joobz, or both of us, else you would have left this thread, which has largely devolved into banality. Instead, you decided to make a post, and thus a comment, and decided to make it obscure enough in the vain hope that, if challenged, you might be able to play it off as just another banality. Of course, then you make the idiotic move of actually challenging the idea that stating "No comment" is not in itself a comment of some kind, even of the literal variety. Please DOC, you're many things, but you're not stupid, and neither are we. You should at least treat us with the respect our intelligence deserves.