It is sometimes useful to test search engines to see how they compare on a standard set of tests. You can determine the breadth of coverage of each search engine by trying successively more complex queries, find out which sites have the largest databases, and get a feel for which sites return better content for the types of searches that interest you.
For example, the following list of test searches let you compare the breadth of coverage of four different Internet search engines. You can try several searches on the same site, or the same search on different sites, and compare the number and type of pages they return.
|history AND ancient|
|history AND modern|
|history AND modern AND american AND west AND gold AND fire|
|collecting AND antique|
|collecting AND art|
|collecting AND art AND greek AND sculpture AND angel|