"Based on data from the spam messages and whois lookups
and the larger groupings of messages, the professional spammers
are, for your convenience in case you want to visit them:...
"So we see spammers evolving: They buy or rent real mail servers
now and they have even started coordinating. Using greylisting has
actually increased the cost of becoming a successful spammer.
"At our end of the game, we stay ahead of their game thanks to
tools like spamd, and several of us dump and share our greytrap
lists. It is even possible to collect IP addresses and feed a large
number at the time to spamdb, but after a little while I grew tired
of the increased manual work decided it was time for a
counterprank. Cleaning up after spammers is no fun, unless you can
have little robot helpers do the heavy lifting."