Oh, now, this is cute:
<div style="overflow: auto; height: 1px;">
I found it in some junk comments that showed up recently. It seem that the theory is people notice junk by looking that the displayed comments, not the management interface. In that case, this renders the links in the comment effectively invisible by putting them in a box that’s just 1 pixel high. The “overflow: auto” prevents the browser from expanding the DIV to accomodate its contents.
I actually like things like this in the junk, as it is easy to check for and is never done by non-junk commentors. Thanks, junk-boy!