PUBLISHER'S NOTE: Please note that, as of 9\/29\/03, all of your valued Network World Fusion newsletters will be delivered to you from nwfnews.com. If you use filters to manage your newsletters based on domain name, please adjust accordingly.This past week, two major anti-spam vendors made significant announcements that signal important developments in the war on spam in the enterprise.Postini announced the Postini Threat Identification Network (PTIN), a real-time service that can identify potential spammers and malicious activities, such as directory-harvest attacks, denial-of-service attacks and other threats.Using the company\u2019s heuristics technology to identify these sources, PTIN will help customers identify IP addresses from which they should not receive e-mail by establishing a rating for each source. The advantage for customers of PTIN is that they can determine who the likely offenders are before receiving spam or other unwanted content. The advantage for sources that have been identified as potentially dangerous is that the service operates in real-time: shortly after a source stops sending unwanted content, they are removed from the threat list.One of the fundamental advantages of PTIN is that it can help an organization thwart directory-harvest attacks, a spammer practice that harvests e-mail addresses from e-mail servers and thereby reduces server performance dramatically.Another major announcement came from Cloudmark, which announced the Cloudmark Rating, an extension of the company\u2019s SpamNet offering. When someone wants to use the rating for broadcast e-mail, such as for a monthly newsletter, they send the e-mail to Cloudmark, which fingerprints the message and then creates a content identifier for it. For those customers running SpamNet or those ISPs that use the free Rating module, the content identifier will serve as a sort of stamp of approval, establishing the particular e-mail as trusted, non-spam messages.A fundamental advantage of Rating is that it will allow more wanted content to pass through spam filters because Cloudmark will, in essence, vouch for that content\u2019s trustworthiness. Another major advantage is that users of SpamNet (which now total more than 600,000) will be able to safely unsubscribe from non-spam content, such as newsletters that they no longer wish to receive without having to click on the \u201cunsubscribe\u201d link in the e-mail.These developments are important because they address two key problems in fighting spam: identifying in real time spammers and sources of threats that can rapidly morph IP addresses; and reducing the number of false positives, a particularly egregious problem for publishers of mass-e-mailed content, such as newsletters.