As the volume of spam and viruses in circulation continues to proliferate, small and midsize enterprises are slowly making it the norm to outsource anti-spam and anti-viruses efforts.

"Absolutely, it is something that is growing," says Scott Petry, the vice president of products and engineering for Postini. "A very small percentage of customers will not talk about the outsourcing model."

Enterprises looking to hand off these tasks will find no shortage of vendors to take them up on it. A number of companies currently compete in this industry sector. Most, but not all, handle both anti-virus (AV) and anti-spam (AS) initiatives. While the AS software is proprietary to each player, most use AV products licensed from established vendors such as McAfee, Symantec, or Trend Micro.

The main outsource players, in addition to Postini, are MailShell, MessageLabs, FrontBridge, and MailWatch. At least one other company, MailSecret, is planning to make the jump from the residential market to the outsourced small business and enterprise AS market within the next month or so, president Frank Bellino told ServerWatch.