Best spam filter

Best spam filter *Est. $20 Compare Prices
Cloudmark DesktopOne Pro is a favorite with experts. Most spam filters support limited email types, but DesktopOne plays nice with all varieties of email, be it POP3, IMAP, Microsoft Exchange or web-based. Installation is quick and easy; the software shouldn't slow down modern PCs, and it can be configured for multiple accounts. DesktopOne's actual anti-spam function is among the most effective around, with few false positives reported. Reviewers say the program's effectiveness wanes when scanning old email in bulk, however.
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Web-based spam filter

Web-based spam filter *Est. $25 per year Compare Prices
ClearMyMail filters email before it reaches a user's inbox. Because it doesn't need to be installed directly onto a computer, it works with any operating system, including Windows, Mac and Linux, as well as portable devices like smartphones. The company says it filters email 18 ways before the email is sent on to the recipient. ClearMyMail does require some setup time, but reviews are consistently positive. ClearMyMail scores particularly well for its low false-positive rate, meaning there's less risk of legitimate emails being blocked. The cost of the one year subscription is per email account, however, so while discounts are available, ClearMyMail can get expensive if you need protection for multiple accounts.

Free spam filter

Critics say no free spam blocker matches the top-rated paid options for performance or ease of use. Still, the free version of Spamfighter gets very good grades for effectiveness. Reviewers praise the program's simplicity. Its network-based filtering means that Spamfighter blocks all spam right from installation, so no "training" is required. However, the free version of Spamfighter attaches ads to outgoing email, something that many find annoying. The only way to disable the ads is to upgrade to the paid version, Spamfighter Pro (*Est. $30).
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Specialized spam filter software keeps your inbox clean

The statistics are startling: Internet security experts say most email -- estimates range from 70 percent to 95 percent -- is actually spam -- mail that's unwanted, unsolicited and/or dangerous. A typical inbox doesn't contain that amount of junk mail, though, because most spam is blocked before it ever reaches the inbox. ISPs and large companies use expensive hardware spam filters, while large web-based email services like Gmail have good results with collaborative filtering, where users identify spam emails. Major email reading software -- such as Microsoft Outlook, Windows Live Mail and Mozilla Thunderbird -- also comes with anti-spam filters.

Thanks to those efforts and increased anti-spam capabilities in Internet security software, finding current reviews of standalone spam filters (also called spam blockers or anti-spam software) is getting more difficult. If your email provider's spam filters are nonexistent or ineffective, however, a standalone spam filter can help clear the junk out of your inbox. Experts have highlighted several programs as standouts.

Best anti-spam software

What to Look For
  • Verify compatibility with your email program.
  • Not all spam filters work with all services.
  • Check to see if you already have a spam filter.
Read More

Experts say that purchasing a full-fledged Internet security suite might not give you the most protection against every type of security threat you might face online. But they add that most provide at least adequate protection against Internet perils. For many users, they are also easier to set up and use than  a collection of separate security programs, such as antivirus, firewall, anti-spyware and a spam filter. Most Internet security suites include all those security components, and several offer extras such as parental control capabilities.

For those who prefer the ease-of-use that an Internet Security Suite can provide, most reviewers say that Norton Internet Security 2012, which is covered in our report on Internet security suites is among the best choices. Its spam filter rates very highly; in's testing, Norton doesn't flag a single legitimate email as junk and it blocks significantly more spam than any other Internet security suite reviewer Neil J. Rubenking has evaluated.

But as effective as Norton is at blocking spam, Rubenking reports that Cloudmark DesktopOne Pro (*Est. $20) is better. Most experts agree that the program -- a refresh of the well-regarded Cloudmark Desktop -- is the new king of the hill for spam filters. While most spam filters work only with email that supports the POP3 protocol, DesktopOne blocks junk mail sent to IMAP, Microsoft Exchange and web-based mail, too. The program runs as a standalone Windows service and keeps tabs on protected accounts even when your email reader isn't open. Reviewers say that installation is a breeze and the community-powered filter is very effective. Rubenking says the program allowed only 2.6 percent of junk email into his test inbox, although reports that the program loses efficiency when massive amounts of messages are scanned at once.

The free Cloudmark DesktopOne Basic software offers the same strong, ad-free spam fighting capabilities and robust IMAP/POP3/Exchange/web mail support of its premium counterpart -- but only for a single email account. The Basic version also loses some of DesktopOne Pro's bells and whistles, such as on-demand scanning, the ability to schedule an automatic purging of the spam folder, technical support from Cloudmark and scanning of emails that are more than a week old. Nevertheless, Rubenking gives both versions a Editors' Choice award for best spam filter.

If you're looking for a free spam filter that supports more than one email account, most experts recommend considering Spamfighter. A paid Spamfighter Pro edition (*Est. $30) is also available. Like Cloudmark DesktopOne, Spamfighter taps into community reports and combines a high blocking rate with a low false positive rate for effective anti-spam protection. The software does have a few drawbacks: Unlike DesktopOne, which supports virtually every type of email, Spamfighter is limited to protecting POP3 email, and it can do so only in Outlook, Outlook Express Windows Mail, Windows Live Mail and Thunderbird. Additionally, the free version is limited to 100 custom whitelist/blacklist entries, and it includes ads in its mail client toolbar and inserts a text ad into outgoing emails.

Spamato and POPFile are two other well-regarded free spam filters, but experts warn that casual users may have trouble training and maintaining these more-technical programs. They also aren't updated regularly, and most reviews are now older.

If you have a computer with limited resources or use an email client or operating system with limited support from traditional software-based spam filters, experts recommend using a web-based spam filter such as ClearMyMail (*Est. $25 per year), a U.K.-based service that also services U.S customers. Incoming email is filtered by the service and deposited in your inbox when you go online. Because it protects the email subscription rather than an individual computer, ClearMyMail works with any operating system, including Windows, Mac, Linux, smartphones and BlackBerry devices. It also works with any POP3 email client, but not webmail accounts unless they offer POP3 support.

Experts say setup is simple and the "18-stage filtration process" is almost perfect at blocking spam while allowing legitimate mail into your inbox. In fact, ClearMyMail will return your monthly fee if you receive a single piece of spam in your email. However, while software-based spam filter subscriptions typically protect all of your email accounts, the web-based ClearMyMail is $25 per year per email account, which could add up quickly if you need protection for several users.

Expert & User Review Sources

Given the scarcity of spam filters and spam filter reviews, finding useful information requires casting a wide net., Web User and each cover several programs, although some reports are dated.'s exhaustive testing-based coverage outshines Web User's and's short reviews. Virus Bulletin provides helpful bimonthly anti-spam certifications. offers its picks for the 10 best premium programs, and contains extensive user reviews. PC World, and PC Advisor all offer helpful one-shot reviews of specific software.

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