trimmed back on the number of discussion groups

I've trimmed back all the discussion groups, so that there's just
this one. Having separate genre discussions (classical/metal/world)
just wasn't working as there wasn't enough discussion traffic on them
to keep 'em going.

So now, at the "forums" page
http://magnatune.com/forums/

it's just
===
Discussion
Anything you want to talk about as long as it's about us.

Announcements
Our delicious propaganda broadcasts.
===

Note that I did *not* combine the memberships, as I don't think
people who joined the genre discussions only would be pleased to see
themselves moved to a busier list.