Web search services are now a major source of information for a growing number of people. Due to the rapid development of the Web, Web-based search engines have become the most important tools for accessing global information resources on the Internet. Although these search engines are easily accessible and highly popular, search engines technology, coverage and systematic evaluation of their characteristic is not often presented to users. On the other hand user need to know more about characteristics of Web search engines to improve the effectiveness of information retrieval. In the presentation general remarks and actual problems with web retrieval will be given and the difference between "visible" and "invisible" web will be emphasized. A short history of search engines and recent tendencies will be shown. The main search engines will be compared according to the most important evaluation criteria. Meta-search engines intelligent agents and web tools will be analyzed too. As the conclusion features, important characteristics and future development of a search engines, which can provide high-value results, will be presented.