Selecting an Email Spam Filter

When choosing an email spam filter, there are many aspects to be considered. Before investing in an anti-spam solution users should make sure the package they are considering meets their needs. Today, most users have the option to enable server-side filtering, or purchase a software package that runs on their computer.

Many ISPs include some type of email spam filter functionality with their connectivity and email hosting services. If it's an option, I recommend users either disable it, or at least set the filter to a conservative setting. The reason for this is that many server based email spam filters don't let you easily view or restore messages that are caught. Even if they do, it's easy to forget to check for blocked messages.

Most filter authors make some claim regarding their product's effectiveness. The most accurate spam catchers catch upwards of 90% of spam, with some catching as much as 98%. Different filters have different levels of success depending on the kind of spam they're dealing with. The best way to verify their claims is to install the software's trial version. If the author doesn't make a trial version available, consider selecting another package.

When choosing a filter, the entire cost of ownership needs to be calculated and taken into account. All email spam filters need to be updated at least periodically. Many manufacturers charge once for purchasing the actual software, and then charge users again for a subscription or for each update. This can radically increase the cost to the user.

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