Allume's SpamCatcher 4 filters out spam for any POP3, IMAP, Hotmail, AOL or Exchange e-mail account when integrated with Microsoft Outlook. A separate "universal" version integrates with Outlook Express. For any other POP3 e-mail client, the universal version provides program access through an icon in the system tray. We evaluated the Outlook version.

In addition to the usual analysis of message content, SpamCatcher employs several other techniques to identify spam. It checks each message's "fingerprint" against an online database to see if other users have flagged it as spam. It rejects messages sent from known spam broadcasters. It looks for "tricks" (attempts to fool antispam analysis), and casts a suspicious eye on messages sent to many recipients. And it specifically blocks phishing scams.

SpamCatcher also offers blacklist/whitelist support beyond the simple ability to block or approve an individual address or an entire domain. You can list all of your e-mail addresses, so the program's analysis will correctly identify messages addressed to you. It handles mailing lists separately, since these typically don't have your address in the "To" field. And you can optionally set it to block all e-mail that's not from an address on your whitelist. If you like, you can block all e-mail that's marked as coming from specific countries, or block mail based on various public blacklists. Finally, you can choose to protect certain senders, countries, or domains from blacklisting.

Alas, this multifaceted protection comes at a price: SpamCatcher is seriously slow. The initial download of 10,000 messages took overnight. In our timed test, SpamCatcher took over an hour to process the same set of messages that Outlook alone downloaded in 4 minutes. Allume verified that the process does slow downloading, and suggested that turning off Spam Network checking might improve speed—at the expense of accuracy. We opted for accuracy.

Despite this choice and despite our initial training, SpamCatcher's ability to distinguish valid mail from spam was only average. It let 13 percent of the spam messages into the in-box and blocked almost 4 percent of the valid messages. Just to check, we changed its spam threshold from Lenient (the default) to Aggressive and rescanned the in-box. This skewed things the other way—only 4 percent of spam got through, but 22 percent of valid mail was blocked. Of course, a well-managed whitelist and blacklist would improve overall accuracy.

SpamCatcher uses a variety of techniques to identify spam, but it slows the downloading of mail in Outlook substantially. Though it does an average job of separating spam from valid mail, we'd be inclined to choose a product that does so without putting the brakes on Outlook.