Has anyone had any experience with this device? Turntide.com. Looks like a
traffic-shaping device designed specifically for cutting down spammers
throughput to your inbound SMTP servers. My main concern is, how does it
make the distinction between legitimate mass-mailings (e.g.: mailing lists
such as this one), and spam? Interesting approach to killing spam though I
SMTP is only about 40% of the spam these days. The rest is via HTTP and DAV (I have seen an upsurge of Hotmail DAV spam since March 18) as per Telepathy - Powering Successful Brands) so you would need a solution that handles all formats.
I would like to draw your attention to a company called Pineapp (www.pineapp.com) that has a product called Antiflood. It handles SMTP and HTTP. For HTTP it analyzes the headers and doesn't allow more than n number of recepients. It allows the admin to set the maximum posts per time frame, has URL blocking time, maximum outgoing recipients, safe URLs not to be time-blocked, etc. It is not really a router but rather an inline transparent proxy box. It is geared for Cybercafes where much spam still originates.
Note: I do not work for Pineapp.