A beta version of Internet Explorer 7 was just recently released, and with it the ability to autodiscover and read syndicated feeds with just a click of a button (more similar to Apple's Safari than Firefox's Livemarks). Unfortunately, its ability to do this will fail on any RSS feed produced by Drupal 4.6, due to lack of support for XML entity doctype declarations (which Drupal 4.6 includes in its RSS). There's nothing wrong with IE, and there's nothing wrong with Drupal - we're both doing the Right Thing in regards to standards. The complete technical reasoning for all this is available, and won't be a problem in the forthcoming Drupal 4.7. There is, however, a one-line fix to your Drupal 4.6 web site that will make the two play nice together:
In your modules/node.module
file, look for this line of code:
$output .= "<!DOCTYPE rss [<!ENTITY % HTMLlat1 PUBLIC \"-//W3C//ENTITIES Latin 1 for XHTML//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml-lat1.ent\">]>\n";
Delete the entire line - be sure not to change anything else. Once you do that and your Drupal cache naturally expires (if you've enabled the cache, that is), IE7 will be able to autodiscover and, more importantly, parse your Drupal 4.6 feed correctly.
If you're using Drupal 4.6's aggregator, a similar deletion in modules/aggrega