I use the Sage RSS reader extension for Firefox, and my web sites' feeds use Last-Modified and ETag headers which Sage respects. If I have 10 feeds from my site and none have updates, Sage merely checks the header and the server sends back a "HTTP/1.0 304 Not Modified". If all RSS readers cached feeds and if all servers serving RSS feeds used Last-Modified, then the load drops massively.
Slashdot Mirror
I use the Sage RSS reader extension for Firefox, and my web sites' feeds use Last-Modified and ETag headers which Sage respects. If I have 10 feeds from my site and none have updates, Sage merely checks the header and the server sends back a "HTTP/1.0 304 Not Modified". If all RSS readers cached feeds and if all servers serving RSS feeds used Last-Modified, then the load drops massively.