On closer inspection these decode as
1.
Code: Select all
<br /><span>JoomSEF SEO by <a href="http://www.artio.net">Artio</a>, sponsored by <a href="http://www.coolhousing.net">Dedicated server</a>.</span>
2.
Code: Select all
JoomSEF SEO by Artio (http://www.artio.net), sponsored by Dedicated server (http://www.coolhousing.com).
3.
Code: Select all
<br /><span>JoomSEF SEO by <a href="http://www.artio.net">Artio</a>.</span>
4.
JoomSEF SEO by Artio (http://www.artio.net).
I'm not a coder so I dont fully understand where this hidden advertising is being used but I cant see any good reason for this advertising to be hidden inside base64 encoding so I can only assume that it is for no good.