I've experienced a pretty significant upswing in spam over the last few weeks,
and I finally had a chance to track it down. Although not responsible for 100%
of the increase, I found that the URIDNSBL isn't getting all of the URLs it
should be.

I've tracked this down to the behavior of
Mail::SpamAssassin::Message::Node::rendered, which seems to be rendering out the
URIs which should be hitting! The messages tend to have two parts - a
text/plain and a text/html. The text/plain doesn't have any URLs which might
hit, and the text/html contains the URL which would hit, but doesn't get passed
into the list of URIs because of how the rendered() routine returns blank HTML.

I was wondering if anyone else has seen this behavior and had any suggestions or
fixed before I take a crack at patching it.