Getting the required information from the multitude sources of information appears to be an uphill task. This is where the search engine comes for making the task easy. This system for recovering information from the large internet database or worldwide web filters the exact information to the web visitor and does so in quick time. The search engine finds the relevant information matching the query searched for. To perform it in quick time, relevance ranking is done based on the different styles adopted by the search engines.
Usually the query is sorted and then information is obtained from database using the most relevant keyword. Searches made on the basis of similarity is performed by probabilistic search engines. Searches made on the basis of exact matches without attending to ranking of relevance or order is done by Boolean search engines. A typical search engine performs indexing of the searches being keyed in for collecting data on the queries. However this indexing is not done by some other types of search engines which upon the search query perform the functions of assessing the keywords and collecting data with resorting to indexing. Index of other search engines are used by Meta search engines to collect data.
A search engine basically works at three levels- accepting websites for listing and using them for information to be used in the database of the search engine, searching of queries based on keywords to retrieve information from its database and ranking of web pages in order of relevance. Normally the most popular websites are linked. A crawler search engine may return only the title or URL or HTML tags of the page visited by it. It can also return the full page text. Most of the search engines depend on the words typed for queries for searching from their database. There are basic as well as more advanced specific searches conducted by a search engine.
It becomes easier to obtain information from search engine if the subject title is made the basis of the search as otherwise lot of web pages with only passing mention of the subject would be thrown up. However search engines allowing truncation are found more helpful. Reaching the relevant information from innumerable websites presents a problem to the searcher. The search engines try to eliminate this problem by assigning relevance score that attempts to find the most relevant matches from the websites.
The frequency of the presence of the searched terms determines the relevance score. The users are allowed by some search engines to give weights to searched words and assign relevance scores themselves. Unfortunately closer the relevance scores, greater is the dependence of the search engines on alphabetical order resulting in showing of lot of web pages that may not contain materials strictly relevant to searched queries or have poor quality contents.
One of the most important features to look for in search engines is the quality of its search tools. Specifying the search and finding out the most appropriate result are basic functions of a search tool. When a search tool of a search engine is not efficient, there would be too many web pages thrown up to confuse the searcher. The open text form of search offers menus to make quick and easy even a Boolean search which otherwise is complex.
More meaningful results are obtained when the searched words appear as URL or heading of a section. Notwithstanding all these, finding a good search engine is sometimes a difficult exercise. More so because all have almost same database and speed. There is hardly any delay in producing
