His name is Mike Corley and he has been around for quite a few years
now.  He does seem to have recently expanded his horizons and is
posting to a more varied selection of newsgroups so, perhaps, he has
just become more visible.

He has got mentions on WikiPedia and there are a number of web pages
that explain (as far you can for someone like him) what he is on
about.  For example,

http://www.bbc.co.uk/dna/h2g2/alabaster/A164404

FWIW, some news servers (news.individual.net for one) are very good at
automatically deleting the posts.

The one thing that really gets my goat about it is that I wish his ISP
would stop him posting this sort of stuff.  It's worse than Spam as it
sits there on the news servers and Google Groups and just clogs it all
up making our lives more hell than if our emails were being spammed :
(

I now read ng's via Google Groups after some problems with news
servers on my ISP and am now reporting all his posts as spam - for
those that want to follow my example, click the 'More Options' link at
the top of the posting and there's the option to do so in the other
links that appear.  I know it's a pretty pointless exercise, but it's
good for my moral...!

Nick