I speak with confidence when I say SpamBayes is perhaps the best spam prevention tool available for Outlook. SpamBayes is an Outlook plugin which implements a learning algorithm to constantly be adapting to both your email habits and new spam threats and features:

• 100% Free.
• Spam detection is based on your email habits. Rules are not determined by a subscription or what the community determines to be spam.
• Works in Exchange environments! All processing is done on the Outlook client, so there is no burden or installation needed on the server.
• Works with POP3 and IMAP configurations.
• Customizable tiered detection (Spam, Suspect, and Not Spam) which can be directed to different Outlook folders.
• Toolbar buttons to easily flag messages as Spam and Not Spam.
• You can “train” SpamBayes based on email already in your Inbox and Junk Folders so you can hit the ground running.

I have now been using it for over a year (with no other spam protection) and I have had, literally, zero spam burdens using the default settings. I get, perhaps 3 spam emails a week which slip into my Inbox and the rest are caught with no false positives at all. People I work with also rave about how awesome this plugin is as well. In fact, it is the only thing we use in our company for spam protection.

I know a tip regarding this ran a while ago but I do think it is deserving of another post. If you use Outlook and don’t already have SpamBayes, go get it!