Hacked Wordpress sites, search engine poisoining?

[foks]

Lately I have seen hacked Wordpress sites with a script that downloads urls from a specific server (please PM me if you need to know the server). Some of the urls are:
http://professorasonia.com.br/treehouse-bums/
http://naughty-america.yournaughtyworld.com/cures-messanger/
http://cstmanzanillo.net/gait-judas/
http://condratiuc.com/fullerton-mcadams/

My first guess was that it was search engine poisoning but I have been unable to find any purpose for it. Tried with some different referers and user-agents but nothing leads to malware.

Does anyone have an idea what's going on?