Cloudmark Desktop 5.3 - Spam Filter Review

Cloudmark Desktop is a great and easy to use junk and phishing mail solution with an excellent spam detection rate and an even better record of avoiding false positives. It is really a pity that Cloudmark Desktop is only available for Outlook, Outlook Express and Mozilla Thunderbird on Windows.

Pros and Cons on Cloudmark Desktop


  • Cloudmark Desktop filters lots of spam very precisely
  • Using a simple concept, Cloudmark Desktop works and is easy to use
  • Cloudmark Desktop blocks phishing attempts, too


  • Cloudmark Desktop is available for Outlook, Outlook Express and Mozilla Thunderbird (Windows) only
  • Cloudmark Desktop is possibly not entirely immune to abuse


  • Cloudmark Desktop is a mail filtering plug-in for Microsoft Outlook, Outlook Express, and Mozilla Thunderbird.
  • Cloudmark Desktop deletes spam immediately or moves it to a dedicated folder, optionally deleting it later.
  • A category is set to allow further filtering of junk mail identified by Cloudmark Desktop.
  • Spam is not identified with automatic filters but by the community of Cloudmark Desktop users.
  • If you mark a message as bad, it will be filtered from other users' Inboxes automatically.
  • The same works for unblocking false positives, too, correcting an erroneous blocking decision.
  • Cloudmark Desktop detects and blocks phishing attempts, in the same manner, it finds junk mail.
  • To prevent abuse, Cloudmark Desktop rates every user according to the quality of past submissions.
  • Additionally, a custom list of trusted senders (can include your Outlook Contacts) helps prevent false positives.
  • Cloudmark Desktop supports Windows 98-Vista, Outlook 2000-7, Outlook Express 5/6 and Mozilla Thunderbird 2.

Review of Cloudmark Desktop

While pondering the implications of various spam fighting strategies is very interesting, there is really only one criterion to measure how good an anti-spam tool is: whether it works. Cloudmark Desktop works.

Instead of relying on filters, Cloudmark Desktop uses the network of its users to identify spam and phishing attempts. Whenever somebody blocks or unblocks a specific message, Cloudmark Desktop learns from that action.

If you think this opens the door for censorship, spammers approving their own messages, and others judging for you what is okay for you to see, rest assured that legitimate mail will hardly ever be touched (though Cloudmark Desktop is not entirely immune to abuse, theoretically).

Cloudmark Desktop not only bans spam, it also bans misuse: everybody must build a reputation by setting accurate blocks for her decisions to be influential.

Both existing and then new users would profit from Cloudmark Desktop being available for other email clients as well, though — as a proxy server maybe.