I've recently had one member in particular who wastes hours of my time asking/commenting about my posts without contributing anything productive towards answering them. I don't want to appear rude to other members (who obviously wouldn't be aware of the history), so I feel obligated to respond to each comment.

In addition, I've noticed that once this member starts participating I am significantly less likely to get input from other members (probably because they either assume that he's solving the problem, or because they get as big a headache as I do trying to read through the comments), and I'm therefore not getting questions answered if this member responds to them.

I don't believe that it would be appropriate and/or helpful to flag the comments because there's nothing grossly wrong with a comment when viewed individually, and as far as I understand flags don't affect an individuals privileges.

Is there anything that I can currently do to limit and/or block this member from commenting/answering my posts, and if not, is this something that would be worthwhile considering in the future?