Cloudmark Desktop

Cloudmark Desktop uses a community of more than a million users to identify spam. Though a little more expensive than some similar spam blockers, reviewers give Cloudmark the edge for its ease of use and light system load. Additionally, reviewers like that legitimate emails are almost never blocked. BullGuard Spamfilter, a free spam filter, also uses community input to identify spam, but includes a rules-based filter as well, which has to be trained by the user for best results. While that makes Spamfilter harder to use, and reports say that Spamfilter doesn't quite match Cloudmark Desktop in effectiveness, BullGuard Spamfilter does have the advantage of being free.

PCMag.com has consistently credible Internet security reviews, and Neil Rubenking's coverage of Cloudmark Desktop is based on considerable testing and analysis. The Tech Herald covers spam filters only on occasion, but Steve Ragan's review is recent and based on months of testing. About.com's write-up doesn't reveal what, if any, testing was done, but is still appropriately balanced.