Typosquatting
Typosquatting (also called URL hijacking) is the practice of registering domain names that are common misspellings of popular websites, hoping to capture mistyped traffic. Typosquatters may display ads, phishing pages, or malware.
Example
Registering 'gooogle.com' (three o's) to capture traffic from users who mistype 'google.com' is a form of typosquatting.