Vote for PowerElf II Server Appliance

The PowerElf II's anti spam filter appliance features stop spam from your network. Unsolicited mail messages not only slows down productivity on the server they also waste end user's time by foring clients to sort messages in order to find relevent emails. It can be used as a standalone mail server or as a proxy mail server.
Features of the PowerElf II spam filter: The filter uses a wide range of heuristic tests to identify "unsolicited commercial email”, header analysis: spammers will attempt to hide their true identify, by fooling you into thinking they've sent a valid mail, or by making you think you must have subscribed to their mailing list at some stage. The filter will try to spot this pattern, text analysis: spam mails often have a characteristic style, and often include text like disclaimers and CYA text. The spam filter can spot these, network tests: The spam filter supports RBLs and Bulk mail checks to help crack down on spammers.