I don't profess to know much about the economics or motivations for spamming but I was impressed today when someone managed to achieve a "Spam Score" of 385 for a comment they posted to my blog. That's a whole order of magnitude higher than any score I've seen before! (My blog is hosted on the blogs.msdn.com site which runs Community Server - Spam Score is a metric defined by the Community Server guys).
I wont post the links for obvious reasons but this is the summary I get in email:
A new Comment has been posted to Slide 7 Event Resources.
Author: Fabolous http://xxxxxxxx.biz/xxx-xxx.html
Status: Not Published
Spam Score: 385
That summary was then followed by about a hundred links to sites of a very dubious nature. I'd like to offer the author a prize but I suspect you probably wont want to identify yourself....