I got an rss feed that said "...because of a recent forum software upgrade, the RSS feed URLs have changed...", but now when I try to relink to the RSS feed I get "The feed could not be loaded because the content is not in a known feed format." from Safari and Mail.app.
Thanks for pointing this out. I didn't know about the problem with the RSS feeds. It must have stopped working at some point. I'll figure it out and post here when it's working again.
OK, there were some feed validation problems that must have come with the new updated forum software. I fixed them and the feed links appear to be working in Safari again.