Why is it that I still can't change my feed address without having to tell everyone subscribed that I've moved to a new address? Yes, I realize this can be accomplished through .htacccess redirects and mod_rewrite (both of which I use plenty of on this site as most of you know), but I think there should be a simple flag at the top of the XML file that tells your aggregator that the feed address has changed and what that address is. This flag would be set for, say, a week, and can (and should) be completely transparent to the subscriber. This would allow the author to change his feed address as many times as he'd like without losing any readers (e.g., those that don't manually update the address when told the old one no longer exists).
I wonder why this hasn't been built into any of the RSS/Atom specifications.