Heuristic analysis sifts through e-mail messages for characteristics and behaviors that are unique to spam messages. CSOs who are looking into antispam products should consult with companies that are already using the technology. Spam signatures work the same way virus signatures do, says Postini marketing VP Doug McLean. CSO: Account renewal rate will tell a lot about how happy the company’s current customers are with the service provider’s existing customers are at the center of their business. For managed service providers, McLean says, the account renewal rate is a big factor.”]