Top10Sites.com is a "smart" metasearch engine - every time you type in a query Top10Sites simultaneously searches a variety of engines, directories, and deep content sites, properly formats the words and syntax for each, compiles their results in a virtual database, eliminates duplicates, and displays them in a uniform manner according to relevance. It's like using multiple search engines, all at the same time.
Founded in 1996 as a master's thesis, Top10Sites.com helped to introduce metasearch to the Internet as one of the first of its kind. Due to its quality results, and the benefits of metasearch, Top10Sites grew rapidly through word of mouth, and quickly became an established search engine on the Internet.
Every time you type in a query at a metasearch engine, they search a series of other search and content sites at the same time, compile their results, and display them either by source or by integrating them in a uniform manner, eliminating duplicates, and resorting them according to relevance. It's like using multiple search engines, all at the same time.
By using a metasearch engine, you get a snapshot of the top results from a variety of search engines (including a variety of types of search engines), providing you with a broad scope of information. Metasearch engines are tolerant of imprecise search terms or inexact use of operators, and tend to return fewer results, but with a greater degree of relevance. They're best used when you've got a general search, as metasearch engines return broad results. Instead of returning every possible result that contains your search term, metasearch will return the most trusted results on the Internet for your search. Metasearch engines also allow you to compare what kinds of results are available on different engine types (indexes, directories, pay-for-placement, etc), or to verify that you haven't missed a great resource provided by another site, other than your favourite search engine (acting as a backup). Overall, they're a great way to save time and find exactly what you're looking for!