Rev, what exactly do these things do when they pop up in the html?
Just links to pr0n sites.
<div style="display:none">
<a href="http://www.escortgalaxy.net/" title="kartal escort">kartal escort</a>
<a href="http://www.nettporno.com/" title="porno">porno</a>
</div>
Hidden links depending on your browser. Div is just a section, with the display:none supposed to hide the content. A is a hyperlink, with href being the location of the link.
There's some other parts, but generally it's just a standard payload drop. The hacker either owns the site or gets paid to direct traffic to the site. Or the sites serve up malware. Or they want to bring their sites up in popularity.