Meet the Search Engines!
Though most people only know a few, there are actually literally hundreds of important search engines. Many of these search engines are specialized - if you are in a niche area, these engines may be powerful ways to bring in more customers.
Types of Search Engines
There are global search engines like Yahoo!, Google, MSN - and others, but also regional search engines in most countries, there are answer-based search engines like www.answers.com, brainboost.com or Yahoo Answers. There people search engines, email based search engines, multimedia search engines, news search engines, blog search engines, job search engines, and many many more.
The World's Leading Search Engine: Google
Google, the world's leading search engine, has country-specific search portals in most of the worlds countries. Google has pioneered the use of formulas to rank web pages in terms of their importance, which effects where they show up. .Google's PageRank algorithm computes a number to each web page for a given search, weighted in relations to the weight of the pages linking to them. This is a departure from the keyword-focused methods of ranking search results, still used by some search engines (MSN for example seems to be closer still to that formula).
Yahoo!: Search and Community
Yahoo! started out as a web directory of websites, organized in a hierarchy, with humans doing the categorizing. Yahoo! Search was the search engine leader before it was displaced by Google, and is still in some categories the world's leading web property as well as the 2nd largest search engine on the web (source: September 2007 Nielsen Netratings.) In part due to its huge communities, Yahoo! is still a global powerhouse in Search. Originally, the actual sorting, ranking, and retrieval of data was done by Yahoo! itself. In 2001 Yahoo!'s search results were delivered by Inktomi and after that by Google (until 2004).
AOL: Captive Audience
AOL is of major interest to search engine marketers because of its captive audience of tens of millions of viewers. At one point, AOL had more than 30 million subscribers around the world. AOL Search has evolved from just another feature in the AOL network, to a complete search engine service, powered by Google. AOL however, has added features to its search, and the results may not always be identical to Google results. Reaching AOL means reaching a large, focused American audience, of Internet savvy searchers, though the numbers are modest in comparison to Yahoo! and Google.
MetaCrawlers: Dogpile, Vivisimo, Mama.com, and others
The metacrawlers combine or list results from a variety of search engines, delivering a blend of the top ranks, organizing the results into categories or folders, or delivering results by engine. Metacrawlers are less used than the major engines, and being on top of the major engines usually carries through to a strong metacrawler presence.
Answer Engines: Brainboost.com Answers.com AskJeeves.com
There are several powerful search engines devoted to delivering answers to questions. These engines are good for quick answers to relatively straight-forward questions. For most commercial purposes, the answer engines are not as relevant as the major engines or the metacrawlers.
CRI Worldwide, a clinical research company, is using SEO techniques to reach far beyond their traditional marketplace of Pennsylvania and New Jersey.