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, vary in the way they rank search results. Some rely more heavily on keywords, whereas others 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 former 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, such as medicine or branches of science, travel, sports, and so on. Examples of targeted search engines
include CitySearch, Yahoo! Travel, and MusicSearch; and like other types of search engines, ranking criteria vary from one search engine 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 (such as pets, sports, locations, and so on).