It is comprised of data on web pages, an index into the data and a mechanism for users to search through the index. The aim of an engine is to provide users an efficient means for finding sites relating to their search need. Search engines can gather and index sites automatically or by hand. Most search engines use a combination of automation and human oversight to fill and index their storehouse. Access to the search engine may be through keyword searching or by drilling down its 'directory', a set of categories and sub-categories, which proceed from the general to the more specific.
Many search engines support both keyword and directory searching.
There is no magic bullet to increase and maintain the number of visitors to your web site. However, there are steps you can take to improve the visibility of the site among search engines and the ranking of its web pages in search results. The first of these is to understand the features common to search engine algorithms, in particular the algorithms used by automated gathering and indexing engines. Use programs and services to help submit your pages into the numerous minor search engines which exist, but submit to the major engines manually. Submit to regional or industry specific engines and directories.