Ad hominem Definition | Definition of Ad hominem at Dictionary.com
JD is referring to the second meaning.
Although when people start out doing the first they often further descend to the second.
Let it be noted by all and sundry that there are Chronicles moderators in time zones around the world -- besides the fact that some of us never sleep anyway. We are particularly alert for signs of trouble having spent most of the holiday season cleaning up messes, and we are going to do whatever it takes to end the escalating ill will. The Chronicles forums are meant to form a community where people can come and share their thoughts without fear of being flamed, mocked, or disparaged, and we intend to see that it continues to be exactly that kind of community.
We know that these are difficult times in the real world and that everyone has frustrations they want to vent, things they are bursting to say. Well, type them in if you must, but please think hard before you hit "Submit" (and after you've done that, give some thought to hitting "Edit" while you still can).