On installing IE 7.0 beta, I noticed that all my website's RSS feeds were broken. Not being one to shy away from desperate measures, I've blew away my Wordpress installation, killed my databases and started fresh. Unfortunately this didn't fix the problem. Turns out the RSS feeds were failing because I had an extra carriage return in my wp-config.php file. Apparently this makes the RSS feed unparsable for Microsoft. I have fixed the problem and I am contacting them about it as well.