[Plugin: Advanced Tag Lists] This plugin breaks your RSS feed!

If you activate this plugin, you will break your RSS feeds.
The first line will be blank.
This KILLS the feed. Feedburner will fail, and it’s twitter and e-mail subs will die with it.
Trust me, I tracked the fault down by disabling ALL plugins and then re-enabling them all, one-by-one. THIS plugin was the culprit!
(It took me about half-an-hour on one site, then I simply disabled this plugin on the second site, et voila..)
It hasn’t been updated in two years, and isn’t compatible with the latest version of WordPress.

http://wordpress.org/extend/plugins/advanced-tag-list/

These are the two sites it affected:
http://www.nervejam.com
http://www.quirkycars.net

As you can see, the’re both OK now.. but that was a showstopper!