Google is now apparently so large that you can use it to fix itself.
I've tried Posterous, Tubmlr, and Wordpress as secondary archives for
the Gallimaufry of Whits Google Group to try to craft a sensible Atom
Feed out of the messages, but all of them semi-inexplicably drop posts
which come from mailing lists. In desperation, I turned to Blogger,
figuring that perhaps Google are either large or ignorous* enough not
to care about list sourced email.

Thankfully, I was right.

I'm redirecting the feed to point to the Blogger one now. There are
still a couple of problems at least. One is that all the posts in the
feed are going to point to Blogger, whereas really I want them to
point to the Google Group. I've tried to fix that by removing the
archives on the Blogger site and not having pages per post, but it
seems that in lieu of this it's just going to link anyway to the front
page. So to get around that I've also added a new footer to messages
that links to the Google Group topics page.

The second problem is with the footer, because even though I'm using a
custom footer, it's still throwing in a malformed footer extension
below that giving an unsubscribe address which doesn't even work
because it doesn't have an @ in it. This has been driving Noah Slater
mad for a while already, and he hasn't found a solution yet. Perhaps
Google will fix it at some point, or perhaps there's already yet
another Google service out there that can be used to fix it.

References:

http://groups.google.com/group/whits/msg/e4c384ed6af744a9
— Shocking Atom Feed Quality

http://groups.google.com/group/whits/browse_thread/thread/7b9e1fe727f67975
— Posterous and Tumblr

* This means ignorant, but in the non-pejorative sense.