CLASSIFICATIONS OF SEARCH ENGINES.

• Search engines can be broken down into three different types (in the broadest of terms): primary, secondary, and targeted. 

 PRIMARY SEARCH ENGINES.

• A primary search engine is the type you think of most often when search engines come to mind. Some index most or all sites on the Web. For example, Yahoo! Google, and MSN are primary (also called major) search engines.

• Primary search engines will generate the majority of the traffic to your web site, and as such will be the primary focus of your SEO efforts. Each primary search engine differs slightly from the others.

For example:

• Lycos has been around much longer than Google, yet Google is the most popular search engine on the Web. Why is that? Most likely because people find that, when searching the Web, Google provides better search results.

• The difference in those search results is all in the search algorithm used to create the search engine. Most primary search engines are also more than just search. Additional features such as e-mail, map-ping, news, and different types of entertainment applications are also available from most of the primary search engine companies. 
• These elements were added long after the search was established, as a way to draw more and more people to the search engine. Although those features don’t change the way people search, they might affect which search engine people choose

 OVERVIEW OF GOOGLE.

• Google is the king of search engines, in part because of the accuracy with which it can pull the results from a search query. 
• Sure, Google offers all kinds of extras like e-mail, a personalized home page, and even productivity applications, but those value-added services are not what made Google popular.  What turned Google into a household word is the accuracy with which the search engine can return search results. 
• This accuracy was developed when the Google designers combined keyword searches with link popularity. The combination of the keywords and the popularity of links to those pages yields a higher accuracy rank than just keywords alone.

• However, it’s important to understand that link popularity and keywords are just two of hundreds of different criteria that search engines can use in ranking the relevancy of web pages.

OVERVIEW OF YAHOO.

• Most people assume that Yahoo! is a search engine, and it is. But it’s also a web directory, which basically means that it’s a list of the different web pages available on the Internet, divided by category and subcategory.
•  In fact, what few people know is that Yahoo! started as the favorites list of the two young men who founded it. Through the acquisition of companies like Inktomi, All the Web, AltaVista, and Overture, Yahoo! gradually gained market share as a search engine.

• Yahoo!, which at one time used Google to search its directory of links, now ranks pages through a combination of the technologies that it acquired over time. However, Yahoo!’s link-ranking capability is not as accurate as Google’s. In addition, Yahoo! also has a paid inclusion program, which some think tends to skew search results in favor of the highest payer.

 OVERVIEW OF MSN.

• MSN’s search capabilities aren’t quite as mature as those of Google or Yahoo! As a result of this immaturity, MSN has not yet developed the in-depth link analysis capabilities of these other primary search engines. 
• MSN relies heavily on web-site content for ranking purposes. However, this may have a beneficial effect for new web sites that are trying to get listed in search engines.

• The link-ranking capabilities of Google and Yahoo! can preclude new web sites from being listed for a period of time after they have been created. This is because (especially where Google is concerned) the quality of the link may be considered during ranking. New links are often ignored until they have been in place for a time.

• Because MSN relies heavily on page content, a web site that is tagged properly and contains a good ratio of keywords will be more likely to be listed — and listed sooner — by the MSN search engine. So, though it’s not the most popular of search engines, it is one of the primaries, and being listed there sooner rather than later will help increase your site traffic.

 SECONDARY SEARCH ENGINES.

• Secondary search engines are targeted at smaller, more specific audiences, although the search engine’s content itself is still general. They don’t generate as much traffic as the primary search engines, but they’re useful for regional and more narrowly focused searches. Examples of secondary search engines include Lycos, LookSmart, Miva, Ask.com, and Espotting.

• Secondary search engines, just like the primary ones, will vary in the way they rank search results. Some will rely more heavily upon keywords, whereas others will rely on reciprocal links. Still others might rely on criteria such as meta tags or some proprietary criteria.

• Secondary search engines should be included in any SEO plan. Though these search engines might not generate as much traffic as the primary search engines, they will still generate valuable traffic that should not be overlooked. 
• Many users of secondary search engines are users because they have some loyalty to that specific search engine.

 For example:

• Many past AOL users who have moved on to broadband Internet service providers still use the AOL search engine whenever possible, because it’s comfortable for them.

 TARGETED SEARCH ENGINES.

• Targeted search engines —  sometimes called topical search engines — are the most specific of them all. These search engines are very narrowly focused, usually to a general topic, like medicine or branches of science, travel, sports, or some other topic.

Examples of targeted search engines include CitySearch, Yahoo! Travel, and MusicSearch, and like other types of search engines, ranking criteria will vary from one to another.

• When considering targeted search engines for SEO purposes, keep in mind that many of these search engines are much more narrowly focused than primary or secondary search engines. Look for the targeted search engines that are relevant to your specific topic (like pets, sports, locations, and so on).