Can't customize results as much as other search engines. Search options easily accessible through pull down menus for advanced searches. Only search engine that gives advertisers a boost in ranking results. Limited ways to refine searches. Includes Special Collections, which lets you search trade and business periodicals along with Web at large.
Special collections does have a fee.
Specialty Search Engines Specific to an area. If you are looking for shareware software, this is the site. Lots of magazines and newspapers have online sites. Search back and current issues, plus a lot more. Let's you submit searches to dozens of different search engines.