The most popular Search Engines in the US currently are: Google, Yahoo!, MSN, AOL& Ask Jeeves

About Google:
67.1 million unique visitors in December 2004*
Google has become the pre-eminent web search engine. It started out in 1999 and has become the largest index in the world, comprising more than 4 billion web pages which can be searched in often less than half a second. If printed, this would result in a stack of paper more than 227 miles high.

About Yahoo!:
49.7 million unique visitors in December 2004*
Yahoo! is one of the best known and most popular Internet portals. It originally started out as just a subject directory, but has grown to become a search engine, directory, and a portal. In Feb. 2004 Yahoo! introduced its own search engine database which appears to be primarily from the search engine Inktomi. When performing a search on Yahoo! you will get category results from their directory, several paid listings from their partner Overture, web sites within their new database. Yahoo! also has an image database similar to Google’s and provides yellow page searches, product searches and news to their users.

About MSN:
37.7 million unique visitors in December 2004*
MSN's new Search Engine, Like Google is based on a page ranking system and will return search results based on relevancy to a user’s search. So far they claim to have over 5 billion web pages indexed. It also features the ability to search MSN Encarta's online Encyclopedia. Images and News searches are also available.

About AOL:
25.4 million unique visitors in December 2004*
AOL’s search service is primarily used by AOL subscribers. It’s search results come from both Google’s database and directory listings provided by the Open Directory Project (DMOZ).

About Ask Jeeves:
11.7 million unique visitors in December 2004*
Ask Jeeves Search Engine ranks search results based not just on the global popularity of sites but also on linking patterns within individual subjects. For example, if many financial-related sites linked to a particular page, that page would have higher results in a financial-related search.

Source: http://www.101webbuilders.com/web_design_seo_news.htm