It's very easy to set your newsreader so you never have to see
anything they say, ever again. Just set a killfile. It's easy. And
if you're using Google Groups (which doesn't natively support that
feature), just use the greasemonkey add-on.
http://www.penney.org/ggkiller.html
Download greasemonkey and the killfile script. Open the extension and
restart your browser. Then use your browser to open the javascript
file, and voila! Google groups now has a button next to each poster
that says, "Ignore User."
You never need to be bothered by someone who posts incessantly - or
anyone who bugs you, for that matter - ever again. I switched a
little while ago, and I gotta say, it's nice.
I cannot recommend this, or rsdnospam.com, enough.
And stats on the most ignored poster(s) to r.s.d.