I just got a spam filter for 550 people up and running at work. I looked at what was out there, weighed up hosted service vs product and I plumped for Easylink SpamWatch. It's basically DNS Blacklists + SpamAssassin with a *very* simple web interface. It's at least 3 times cheaper than Postini, but doesn't do virus scanning or quarantine. Easylink also have a more fully-featured service called MailWatch which does the virus stuff too.
SpamWatch is US-based and costs us $0.50 per user per month + $250 one-time setup. I don't know if there's a minimum amount per domain though (it would be logical).
I just got a spam filter for 550 people up and running at work. I looked at what was out there, weighed up hosted service vs product and I plumped for Easylink SpamWatch. It's basically DNS Blacklists + SpamAssassin with a *very* simple web interface. It's at least 3 times cheaper than Postini, but doesn't do virus scanning or quarantine. Easylink also have a more fully-featured service called MailWatch which does the virus stuff too.
SpamWatch is US-based and costs us $0.50 per user per month + $250 one-time setup. I don't know if there's a minimum amount per domain though (it would be logical).