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Contents - Search Engine Categories
Locating Search EnginesDue to the extensive proliferation of general and specialty search engines on the internet, various web sites have been created to help internet users locate resources which span the entire globe. While many are still in their infancy and lack the user-friendly features of most general search engines, the directory structure of most of these sites nevertheless enables the patient user to locate search engines appropriate to their tastes. As the topic-specific search engines continue to multiply, it is reasonable to expect greater business interest in developing these resources more fully.
General Free Text Search EnginesTraditional search engines, which primarily rely upon first generation automatic indexing programs, are typically regarded as the most relevant and most popular search engines on the internet. Even so, many are now employing several second generation search systems to supplement those search results gained through “crawling” the internet. Additionally, most of the following sites also include topic-specific search engines as an option.
The ProblemBecause of the ever-expanding nature of the internet, simple keyword searches routinely display results in the tens and hundreds of millions. Even using more specific search words and advanced search techniques may still provide the typical search engine user with several thousand results. Despite those staggering numbers, the relevancy of the information displayed in these large search results still suffers when the search engine in use is incapable of searching results that would otherwise be discovered by other search engines. Moreover, most major search engines are only recently adding the capability to search the databases commonly excluded from search engine indexes (such as scientific databases), leaving large portions of the internet undiscovered by the more general search engines. How Metasearch Engines WorkMetasearch engines combine the search results of several other search engines and directories to create their results. Therefore, they do not maintain an index, “crawl” the internet, or accept web address submissions. Instead, these search engines send the search query to the underlying individual search engines. After collecting the results of the individual search engines, the metasearch engine removes duplicate links, applies its own algorithm, then ranks and displays the information. ProsSaves time. Because the metasearch engine queries several individual sites simultaneously, the metasearch engine user can focus their efforts on one site while receiving results from many. ConsWhile this offers a more comprehensive view of the overall pages available in many cases, the results are limited by the quality of the underlying search engines. In addition, these search engines have a major disadvantage due to the failure of some to adequately “translate” the search queries into the various search forms required by the underlying search engines. Though most translate simple Boolean searches adequately, many have difficulty translating advanced search functions into syntax that each of the underlying search engines can understand. Examples * Also included as a clustering search engine.
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Clustering Search EnginesThe ProblemSearch engine indexes, which now hold billions of web pages, simply produce so many results that more and more search engine users must simply decide to stop the search when they no longer have time to assess and evaluate the results. Even when advanced search techniques are coupled with unique search terms, thousands of results are still likely to occur. The organization of most search engine results only compounds the problem. The endless hierarchical scroll of the search results in the typical search engine potentially hides results relevant to the user in the thousands or millions of listed web sites. How Clustering Search Engines WorkClustering search engines attempt to conquer this “information overload” by providing a new method to present the search results. Instead of presenting long lists of results, the cluster search engine groups the results according to common topics or subjects contained within the website listings. Each clustering search engine uses its own method to reach these results. While some clustering search engines, such as iBoogie, use predefined folders from an internet directory, most of the examples below create the clusters dynamically, after the search is completed. Selecting a specific cluster enables the user to limit the subject matter to only those websites defined to fit within the selected topic. The technology is used on both regular search engines and metasearch engines. Further, as competition among search engines continues to heat up, even first generation search engines are trying to update the organization of their existing search methods. ProsImproves search results and allows for easy refinement of a broad search. In addition, the listing of categories in response to the search may actually provide topics and subjects that were not anticipated in the original search, but are nonetheless relevant to the search engine user. ConsThe technology is still in its infancy. Currently some of the search engines eliminate results that they are unable to categorize into an appropriate cluster.
Examples
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Topic-Specific Search EnginesUsing many of the above technologies, the categories of topic-specific search engines are seemingly endless. These search engines allow the user to focus upon a specific topic even before the search is conducted. Though topic-specific search engines are included as an option on several general search engines such as Google, Yahoo Search, Lycos, and MSN, these examples do not begin to illustrate the extent of this category’s growth. Beyond the news, audio, video, and images search engines included with most general search engines, the range of topic-specific search engines is wide enough to include online books, blogs, discussion groups, science articles, pet affinity sites, antiques, and even teddy bears. Though typically utilizing the search capabilities of general search engines, the topic-specific search engines are often limited to specific websites relevant to the topic, including some deep web databases that would otherwise be overlooked by general search engines. For examples of topic specific search engines, see the Search Engine Guide: Search Engines Directory. Furthering the increase in topic-specific search engines is the do-it-your-self capability offered by the technology. As illustrated by Gigablast.com’s Custom Topic Search, not only is it possible to create the search engine, but even the amateur web designer can now stipulate exactly which web addresses to search.
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