I've seen it. It usually is the result of being trolled. The "troll" user of software A starts poking at the user of software B in a way that on the surface looks like an editor joke, but is actually about hte person. Something like "this code looks like it was written in X" or "how can an X user have completed bug #11". After a while it can get under the skin, but if the target is not paying enough attention, or is you know, working, the result can be a full on editor war.