Yes, that issue cropped up a few weeks ago:
http://groups.google.com/group/TiddlyWiki/t/340d88517f7e290d
Other groups seem to be having the same problem:
http://groups.google.com/group/Is-Something-Broken/t/8561acd89999f85b
No word from Google yet, sadly.
> Eventually I found out that by using the advanced search option on the
> google groups main page it is possible to get 92 results for the same
> search (drag file group:TiddlyWiki)
That's a good workaround - thanks for sharing!
-- F.
It appears that's happened now:
http://www.wired.com/epicenter/2009/10/usenet_fix/
-- F.