No single software can outwit a million human minds working together to rid the world of spam. This seems to be the gist of Cloudmark’s Desktop 5.3.3 for Microsoft Outlook. It's a community-based spam filter. It strips out spam from any e-mail account that your e-mail client supports. It works by reducing a spam message marked by a community message into a unique fingerprint, then sends that fingerprint to a central database. If the database receives enough reports for the exact same message (based on the fingerprint), it concludes that the message really is spam and blocks it for all other members. To keep people from gaming the system, Cloudmark maintains a trust rating for every user that increases as you continually report real spam messages. There is no performance hit when reading your mail since the analysis happens within the e-mail client, after the messages have arrived. The reviewer noted that during testing, out of 5,000 messages, Cloudmark Desktop didn't misidentify a single valid message from an individual as spam. Also, only 2 percent of the undeniable spam made it into the inbox. The strength of Cloudmark in blocking spam and the wider variety of e-mail clients supported make it an excellent choice.