No cross-jacking. No phony niceties, especially on message boards. No phoniness in general. Own it. Man up.
"Wow. Great post. I know the prior 23 people said the same thing, but thanks for sharing." This is an example of CJ or cross-jacking. Do not do this.
NOCJ approach #1: mods delete the b.s. thread
NOCJ approach #2: mods do not respond, thus encouraging the behavior.
NOCJ approach #3: "STFU!"