Ok, I had to do it...
I added an incremental feed. The server keeps track of when you last queried, and only answers with new content since then (if any). Some of the proposals I've seen floated for this rely on client-tool help with cookies, or something in the feed. This solution does not rely on the client at all.
Comments
Caching based on IP address
[David Shaffer] May 15, 2003 9:39:48.772
Yes but for those of us behind some kind of proxy server I'm guessing it will only send me posts since the last time someone at my institution accessed your blog. Those of us in this situation can continue to use your old feed, of course ;-)