Spam is of course a modern blight, but until recently I thought I'd found the closest thing to a perfect solution. This was the spam filter built into Gmail. Compared with any of the other email services on which I've maintained accounts -- Yahoo, Hotmail, the Atlantic's in-house system, until recently AOL -- Gmail seemed better by both measures of anti-spam effectiveness. It had very few "false negatives" (spam it should have trapped but mistakenly let through) and virtually no "false positives" (messages I wanted to see but that it mistakenly trapped).
Or so I thought.