Another long-standing character common to forums is the Peacekeeper. This guy has been a regular at a particular site as long as the proprietor, but his goal as a participant has somehow devolved from saying something interesting to keeping the peace--and he has no problem peppering every thread with his efforts to intervene as Mr. Manners.
"Hey now, that's not appropriate," he may say. Or, "Let's watch the language, okay?"
Though the Peacekeeper's intentions are good, his actions end up clogging the forum with pages of useless and often long-winded discussions of propriety that are every bit as annoying as the attacks themselves. Worse, unlike the Antagonizer's antics, the Peacekeeper's contributions can be virtually impossible to silence, even if you're the site's moderator. After all, how do you tactfully tell a guy to stop pacifying?