You might have noticed what happens if you make such a mistake. Perhaps you've seen a pop-up ad bearing the logo of a page you actually wanted but pitching a prize for entering a contest or filling out a survey. Or maybe you've just seen a page full of clickable links to sites selling related goods or services.
But sometimes the misdirection is more subtle - and risky. For instance, some recent, accidental visitors to "www.wallmat.com"; downloaded malware onto their computers, according to an advisory from Google.
That's just one of the dangers, according to a recent report from Websense, a California "content security" company that provides blocking services for businesses that want to keep employees from visiting problematic sites, such as those pitching online pornography and gambling.
Chris Astacio, Websense's manager of security research, says "typosquatting" puts careless Internet users at risk of scams such as phishing, in which look-alike web pages are designed to steal account numbers, passwords, and other sensitive data. The worst sites expose visitors to malware, perhaps drawing them into botnets used by criminal enterprises.
The biggest names on the web are common targets. Earlier this year, Facebook sued a group of typosquatters it said were harming the company's business and reputation.
Astacio said Websense is continually on the watch for typosquatting. This fall, it documented more than 2,000 such addresses, including a large number that seemed to center on a set of legitimate British retailers such as Homebase and Mothercare.
"This year, we noticed that it happened more en masse," says Astacio, who described the related sites as a "typosquatting hive": a collection of domains apparently controlled by a single group. "This one looked like it was aimed at CyberMonday," the Monday after Thanksgiving that is a peak day for many online retailers.
