A Perplexing Form of Spam - Theories?

[Acapulco]

Quite often lately I have been coming across a huge & complex network of machine-generated doorway pages of basically nonsensical sites.

Here is just one example of a trio of tens of thousands of scraper pages:
xhttp://scienster.com/mentagon.chtml?concentration
xhttp://pobiang.halard.com/
xhttp://punctualthisagent.blogspot.com/

The network seems to form a triangle of sorts, but I'm not exactly sure who is receiving benefit (i.e., the goal behind the strategy). Sometimes these pages link to poker & other affiliate sites, so perhaps the goal is to generate backlinks from the pages. Since the pages are also linking to many authority sites (from which they steal content to build their pages), perhaps they are trying to “associate” their affiliate site with these authorities. But that seems like a huge bother just for that purpose. Perhaps it is adsense, but not all the involved sites have adsense, and I can't see them getting much traffic anyway.

Some of the pages also have hidden links to other sites in their network if you View Source, or they simply link to other sites in the network with numbers. They don't even use their root domains, I guess so that it is a little harder to tie them all together in a linear fashion. To a dumb search engine (i.e., at least MSN & Yahoo), the network might appear to be more random simply due to the enormous quantity of pages involved.

Are these just another form of adsense scraper sites, or is it a network trying to generate backlinks, or something else altogether? Theories?

(EDIT NOTE: Sorry, forgot to add "x"s to not give them links.)