This is a popular trick to lure users to a malicious site. Personally, I seldom make typos when entering words into my favorite search engines; but as they say, there’s always a first time for everything! Better check your inputs before hitting that search button!
More details can be found in this article from Websense:
“This lure relies upon the eventuality that a user will make a typo while entering a term into a search engine. There are an endless number of possible typographical errors for any given term, but with a few algorithms and statistics you can significantly narrow down the number of possibilities. Attackers have been doing this for years and have become very good at predicting the most common typos for each keyword.
(snip)
Someone out there is always trying to get you to visit their website and sometimes the simplest tricks work wonders. The next time you are making a search on the Internet, take an extra second to make sure you got the results you expected before you start following links. One letter can mean the difference between arriving at your online banking site or ending up with a desktop of Spyware. ”