Typosquatting is a technique exploiting the probability that a certain number of users will sooner or later make a typing error by hitting a key close to the one for the correct letter, or by omitting a letter or making a mistake with the domain name (e.g. .com instead of .co.uk). Thousands of addresses differing from very well known sites by a small detail have been identified.
In some cases there is no actual dishonesty, but simply a trick. Thus www.whitehouse.com (and not .gov) corresponds to a real estate firm in the United States. www.gogle.fr is a commercial site. But a few years ago www.gogle.com was a pornographic site, a more serious state of affairs. Google has now bought this address which redirects to the official Google site.
Pornographic sites are of course likely to exploit typosquatting. Another dishonest use is to redirect customers from one site to another competitor site. Finally, a related technique is used to divert emails sent to well known addresses.
It can be expected that the example of www.gookle.com (don't go there - it sends out spyware!) will soon be widely followed as a means of spreading viruses. It is true that the name of the person registering a domain name is known, but it is sadly also true that if they live in certain countries the tricksters do not run much of a risk.
As well as keeping your web browsing tools up to date there are two other steps you can take: Internet Explorer will be the main target for sending malware in this way. By using another browser you will be much safer. "Vaccinating" your computer with the free software Spywareblaster will protect you against thousands of malware threats. And finally, some anti-spyware (such as Spybot Search and Destroy) has a resident module that warns you if a program (probably malevolent) is trying to install itself surreptitiously on your computer.
But in future be very careful when typing the address of very well known sites: these are of course the preferred targets for this type of action.