We looked at a number of plug-in solutions for Outlook and the one we opted for was Cloudmark Desktop which costs $39.99 for a 12-month subscription. Installation is simple after downloading the software from their downloads site. Once installed, Cloudmark integrates a simple toolbar into Outlook as shown in the picture and creates a Spam mail folder. As mail comes in from the mail server, Cloudmark evaluates it and moves it to the spam folder if it is known spam. If junk mail arrives in your inbox then you can mark it as spam by clicking on the Block Spam button in the toolbar. When a specific number of people report a particular e-mail as spam it is added to the Cloudmark database and will henceforth be treated as spam.
The attraction of Cloudmark Desktop is its simplicity, requiring a minimum of user interaction, and its success rate in detecting spam straight out of the box. A recommended addition if you want to use Microsoft Outlook and successfully manage spam. Note that a version is also available for Outlook Express.