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How Apple's Spam Filter Stacks Up

I won't say I don't receive pitches for the occasional mortgage discount or Vegas vacation, the latest performance-enhancing elixir or anatomical wonder pills. Somehow those untidy and still slightly amusing offenders still wriggle past my defenses. In general, though, I've had good results with a built-in spam stopper in Apple Computer's (Nasdaq: AAPL) Mail program, which I've used daily since it was released with the Jaguar update of OS X last year. Amid the frantic hand-wringing over unwanted e-mail, I've heard relatively little mention of this program, so I thought I'd offer my impressions gleaned from nearly 10 months of using the product.

On the whole, the Mail client in OS X does an excellent job of sorting out the refuse. Of the 125 or so daily e-mails I have received in the last week, about 700 went straight to the Junk folder that Apple Mail sets up. Despite the annoying come-ons that get through the filter, my Inbox remains relatively free of everything but real correspondence. Just as important, my perusal of the Junk folder on most days shows that little or nothing in the way of real mail has been misfiled.

Sniffing Out Spam

We all know spam when we see it, but enabling a computer to recognize it is the challenge and the goal of spam programs. Apple says it has gone beyond the approach taken by most filters, which is to look for words or addresses only in the header information of an e-mail . A technology that Apple calls "latent adaptive semantic analysis" is a process of searching through a message's entire text for patterns of words in combination, according to Apple representative Ken Bereskin. He says the company has speech experts on staff who have helped develop a unique approach to parsing combinations of words.

The filter in Mail also allows you to train the program by flagging messages that the software thinks are Junk, then offering you the option to veto those judgments. In addition, a rules screen lets you specify specific senders or content that should automatically be swept into the Junk folder.

Happily, I was able to avoid all of this complexity and simply turn Mail's filter to "automatic," at which point it absconds with suspected messages and dumps them in the Junk folder. That means there was almost no startup penalty for using the filter, which was a big relief in turning the thing on in the first place. Of the few messages that were misfiled early on, it was easy to set Mail straight by clicking the "not junk" button in the program's control bar. As rates have come down, I've considered adding the word "mortgage" to the program's default junk filter, but I find it's easy enough to click the "junk" button and dispatch the occasional problem e-mail to the dustbin of history.

Spam 'Em Back

Apple's Mail has its limitations. Many institutions use a central spam-filtering application on the server, which can insert into the header field of messages a tag such as "X-Spam-Flag." This flag can tell your e-mail client that the message is spam, and the client then can handle it appropriately. Apple's Mail doesn't automatically include X-Spam-Flag as a rule, which means it doesn't work as a good citizen out of the box.

However, if you're like me and work out of a home office, or if you don't want an institution filtering your mail, this may not bother you. I've often found the bulk mail folder, for example, to be an unwelcome feature of free mail services such as Yahoo (Nasdaq: YHOO) and Hotmail. Aside from misfiling some things, it seems like a crude method that fails to diminish the tide of crud flowing to these free addresses. It's easy enough to set up a rule in Mail to support the spam header if you really want to.

More important, rules for spam in the Mail program do not allow recipients to automatically "bounce" junk mail back to the sender. This is a curious omission for an otherwise well-designed program. The bounce function effectively tells spammers you're not in, which may compel them to take you off their mailing list. Then again, the return address listed on a spam message may belong to just another poor shlub on the list, so bouncing messages may do no more than further the harassment.

A Step Forward

To be fair, not everyone is thrilled with the results of the Mail program. As one blogger has written, some find the filter catches only a small percentage of their junk. I can't rightly say why results vary so much, but it may be that the Apple filter is not a heavy lifter for those who receive literally hundreds of spam messages per day.

From my perspective, though, Apple's filter is a step in the right direction. It may not be the best filter, but it comes with the platform, it's easy to use, and it works well most of the time. I'm looking forward to the next version, with the release of the Panther update to OS X, in which we will hopefully see an option to automatically forward our spam to Senator Conrad Burns.