[Editor\u2019s Note: Denise Pappalardo is off today. In place of her newsletter we present this news story from the Service Provider Networks section of Network World Fusion. Enjoy.]John Knapp, executive vice president at Producers Assistance, a personnel company in Houston that serves the energy industry, was ready to give up on e-mail.\u201cI was getting 200 spam messages a day,\u201d Knapp says. \u201cIt was uncontrollable.\u201dHe wanted to filter out the spam, but wasn\u2019t happy about the prospect of having to implement and manage antispam software. Instead, he signed up for a hosted service from his messaging application service provider Interliant, which offers a managed spam-blocking and virus-detection service through its partner, Postini.Managed infrastructure company NaviSite, which acquired Interliant and its spam- and virus-blocking service earlier this year, expects other companies to follow Knapp\u2019s lead. Last week, NaviSite announced a special introductory offer for its Managed Spam Filtering service that waives setup charges and discounts the service 25% for customers who sign one-year contracts. John Whiteside, director of product marketing for NaviSite\u2019s messaging services, says pricing for the service varies but typically includes a $250 setup fee and \u201ca couple of dollars per mailbox per month.\u201dPostini\u2019s technology analyzes IP addresses and all text and HTML parts of a message against \u201cheuristics-based expressions\u201d in real time to weed out spam. End users can modify the filters to ensure that legitimate e-mail doesn\u2019t get blocked.While dozens of companies - such as NetIQ, Symantec and Tumbleweed Communications - offer antispam products, only a handful, including FrontBridge Technologies and Postini, offer spam filtering as a hosted service. Both companies let customers set filtering controls, but Masha Khmartseva, a senior analyst at Radicati Group, says Postini lets end users set up their own profiles, rather than requiring a mail administrator or authorized user do it.\u00a0The benefit of a hosted service, analysts say, is that companies don\u2019t have to deal with deploying, managing and updating the software. In addition, companies can save money on bandwidth because messages are scanned in remote data centers, so inappropriate messages never enter customer networks.\u201cThere is no question in my mind that we\u2019re saving money,\u201d says Knapp, who says his 200 unwelcome e-mails per day have been whittled to about a dozen. \u201cI expect to save money on the amount of bandwidth that we\u2019re not paying for, because that\u2019s how we pay for our mail hosting. The more stuff we move back and forth, the more we pay, so by eliminating it from ever coming here, we\u2019re cutting down the cost of our service.\u201dKhmartseva says NaviSite\u2019s decision to offer the managed spam-filtering service makes sense.\u201cNaviSite has a lot of other services that it offers, so customers can get a complete solution,\u201d Khmartseva says.To help companies determine the financial effect that spam is having on their bottom line, NaviSite has set up a spam cost estimator on its Web site.