The Typo Millionaires -Slate:
For almost as long as the Web has existed, there's been a thriving economy of sites, services, and software vying to grab you as soon as your mistype a URL. During the boom time, a decade ago, there was a woman who'd goosed her income by developing software that took a list of the most-visited Web sites, calculated the most likely typos that surfers would make trying to reach them, and automatically registered those domains if they were available. She then raked it in by serving ads to the accidental tourists who landed on her sites.

Various studies have estimated that 10% - 20% of all hand-entered URLs are mistyped, adding up to at least 20 million wrong numbers per day. Typo traffic supposedly generated a million bucks a year for John "Cupcake Party" Zuccarini, a Florida man who registered as many as 3,000 typos of popular domains. God bless American entrepreneurs, I say, but Zuccarini made the mistake of serving porn to kids who misspelled sites like cartoonnetwork.com. He was arrested in 2003 for "us[ing] a misleading Web address to draw children to pornography."

There's another typo-squatting game that only the big guys can play. In 2001, Microsoft rejiggered Internet Explorer so that if you type in a URL that doesn't exist, the browser will redirect you to a Microsoft page. The current version says something like, "We can't find srate.com," with a tempting search box immediately below it—a blatant ploy to drive traffic to MSN Search.

In 2003, VeriSign, the company in charge of .com and .net domain names, added a wildcard entry to their database that matched any domain that wasn't already registered. Any user who requested a nonexistent domain got a VeriSign page instead, and the company planned to sell links to the correct sites on this landing page. You probably don't remember the episode, because a day later the geeks who maintain the Net's domain-name server software released an emergency upgrade that neutered VeriSign's plans.