An ideal anti-spam system rejects messages which are both bulk and unsolicited, letting pass those messages which are of specific personal relevance to the recipient (not "bulk"), and those which the recipient has expressly requested (not "unsolicited"). When phrased in these terms, spam filtering is obviously a task for a well-informed intelligent agent of immense sophistication—quite beyond our current ability to construct. Anything less is a weak approximation at best.

With content filter, the network manager has complete control over what applications the staff can use and what material they can browse in order to prevent abuse—something that even a firewall cannot do. Optimize your network and discipline your workforce by making them use office hours and bandwidth for your business and not their pleasure.