Intego's Personal Antispam X5 10.5.2 is a solid anti-spam program, as long as you're using Mail ( ) or Entourage ( ) (the program supports both POP and IMAP protocols, but only in those two applications). Installation is easy and (if you're using Mail) automatic, thanks to a setup assistant. If you're using Entourage, there's some manual setup required, but informational windows appear over the Entourage window that explain what you need to do; the procedure, though more complex than the seamless process for Mail, is fairly straightforward. Personal Antispam also installs Intego's NetUpdate, which requires a restart to activate, and which runs in the background, watching for updates to Personal Antispam's filters. NetUpdate resides in your menu bar, and to use it, you'll need to create an account on Intego's server via NetUpdate's preferences. Once that's done, its operation is automatic.

Basic training

After installation, Personal Antispam needs to be trained with both spam and non-spam (ham) messages. You do this by selecting a number of spam messages and then using the new Mailbox menu item in Mail (or the Scripts menu in Entourage) to mark them as spam. You do the same thing with ham messages, but mark them as good. Once a message has been trained as spam, it will be moved into a spam folder, and can then be deleted, either automatically or on a schedule by Personal Antispam. Marking a large batch of messages as either spam or ham can be time consuming; it took a couple minutes to mark a batch of 300 or so.

If you have more than one e-mail account, you'll run into an problem with Personal Antispam when you mark a captured spam message as good. If the message was originally addressed to your main (first) account, then everything will be fine. But if the message was sent to any of your other accounts, when you mark it as good, it will be moved to your default account, instead of into the account to which it was sent. When I asked Intego about this issue, they stated that the program is working as designed, and that most people have just one e-mail account.

Even after training, I found that Personal Antispam's filtering wasn't quite as good as that of SpamSieve or SpamSweep. There were more false positives (legitimate messages treated as spam), and more seemingly obvious spam messages that made it through the filters. Still, the program did a very good job of reducing the load of junk in my inbox, and it definitely improved with time and additional training.

Methodology

Personal Antispam features a number of methods for trapping spam, all of which are configured in the Personal Antispam application. You can launch this program from the NetUpdate menu bar icon, or via the menu in Mail or Entourage. Personal Antispam has a pleasant interface that's well designed and never looks busy. There are six configurable filters within Personal Antispam: A general filter, which looks at things like encoding and message format; lexical filters, which is what Personal Antispam calls a Bayesian filter; a whitelist and blacklist of addresses, message headers, content or layout, URLs, and more; a URL filter, which traps messages with links to certain top-level domains; and an attachment filter that traps messages containing certain types of attachments. The program also features some summary statistics on the program's effectiveness. Though its statistics aren't nearly as thorough as those of SpamSieve, they’re better than those found in the other anti-spam programs. With the exception of the URL filter, all of these filters are customizable—you can add and remove entries from the lexical database, the whitelist, or the blacklist, and add or remove attachment types from the attachments filter.

The main screen in Personal Antispam shows you how many messages have been handled by each filter type, letting you see just how much spam you've been spared. There are some options within each filter that let you control how it works. Oddly, some settings that help the program perform better are disabled by default. In the Lexical section, for instance, enabling "Train automatically with new messages" improves the program's Bayesian filters by automatically adding words from ham and spam messages to its dictionary. I enabled this feature, as well as settings that automatically add the senders of ham and spam messages to the whitelist and blacklist, respectively. Explanations for all these settings, as well as more detail on how the filters work, are contained in the well-written and thorough manual.

Macworld's buying advice

While Personal Antispam X5 10.5.2 is effective at trapping spam, it wasn't quite as good as SpamSieve or SpamSweep (the two best programs out of several I tested recently) at filtering out my spam. It's also more expensive than any of the other anit-spam solutions—not only up front, but there's an annual $30 subscription if you want to keep the URL filters and spam keywords up to date. Personally, I don't see the subscription service as being worth its cost, given you can manually tag any message as spam (which will blacklist it), or modify the filters yourself, if you find certain spams reaching your inbox. The higher cost, poorer performance, and limited client support (it only works with Mail and Entourage) keep Personal Antispam from receiving top marks, but it's still a very good spam fighting solution.

[Rob Griffiths is a Macworld senior editor.]

Updated at 6:27am Pacific time on July 7th, 2009, to correct an inaccuracy concerning the annual filter subscription service.