Typosquatting is also called URL hijacking. It is a Black Hat SEO Technique which is normally exercised to take advantage of an established trademark or the reputation of a brand name. Here, the hijacker builds a website which looks completely similar to the original website of an established brand name but the domain name has a small typographical difference.
When the visitors visit this website, they do not recognize that this is not the original one. Such websites may at times sell the products which are in competition with the original website but one of the huge objects is to steal your information like passwords, credit card details etc.