How much money is Google making from the world's typo-squatters? God only knows. Or rather: God, Eric Schmidt, Sergey Brin, Larry Page, and a few Oompah Loompahs inside their Mountain View Chocolate Factory.

According to a recent study from McAfee and Harvard prof/cyber watchdog Ben Edelman - which relies on web data from May 2008 - at least 80,000 domains are typo-squatting on America's 2,000 most popular web sites, just waiting for innocent web users to misspell or mistype their next url. And 80 per cent of those typo-squatting domains are funded through Google AdSense.

For instance, the study (PDF) says, 742 domains sit just a few misplaced characters from freecreditreport.com, and 327 are shadowing cartoonnetwork.com. "Cartoon Network with three Os. Cartoon Network with two Ts. Cartoon Network that starts with a k. More ways to misspell Cartoon Network than you ever imagined," Edelman tells The Reg. "And almost all of them serve Google ads."

In the US, typo-squatting is against the law. The 1999 Anti-Cybersquatting Consumer Protection Act (ACPA) prohibits anyone from "registering or using" domains misleadingly similar to a trademark or famous name. Yet Google is making money from typo-squatters - most likely a great deal of money. The trouble - as usual - is that there's no window into Google's black box of an ad platform. At least not yet.

Edelman is among the team of lawyers that filed a class action suit against Google in June 2007, accusing the ad broker of violating the ACPA, and he's confident that as part of the suit's discovery process, Google will have no choice but to reveal how much it's pulling in from typo-squatters.

In October 2007, Dell brought suit against 16 so-called domain parkers, claiming they were squatting on its trademarks, and a court freeze order indicated those 16 outfits were raking in as much $2m a month from Google ads - after Google took its cut.

Under the freeze, Google was ordered to shuttle a portion of the defendants' ad revenue into an account for safe keeping. Each month, the order said, the first million should go into the frozen account and the second million should go to the defendants. If revenues top $2m, the order said, half of what's left should be frozen too.

But that's just 16 companies. And who knows how high those revenues really went.