There are 4,200 dedicated and real search engines listed online. At the present time, there are only six major plasyers: Google, yahoo!, AOL, Alexa, MSN Search and ask. Com. They are leading in the market (and traffic) of search engine business, and search engine companies are businesses.
The majority of the search engines acound the world are powered by those major search engine, eg. AOL and Bloomberg.com also display google results.