The Auto-hyperlink URLs WordPress plugin is very cool, but I found a gnarly little bug in it while I was viewing this post:

Try posting something like this:

Here's a 
<a href="http://email.about.com/cs/wincleanreviews/gr/ecleaner.htm">
review from About.com
</a>.

This gets rendered as:

Here’s a review from About.com.

where the HTML source looks like this:

Here’s a 
<a href="http://email.about.com/cs/wincleanreviews/gr/ecleaner.htm">
review from 
<a href="http://About.com" title="http://About.com" target="_blank">About.com</a></a>.

Unfortunately, it tries to linkify About.com even though it’s already inside a link. This causes it to fail XHTML validation, which is what made me notice this bug in the first place.