MetaCrawler doesn't maintain its own database. It sends your queries to nine different services, Open Text, Lycos, WebCrawler, InfoSeek, Excite, Inktomi, Alta Vista, Yahoo, and Galaxy.
Parenthesis mark a collection of words as a phrase.
Words in a phrase will only count as hits if they appear relatively close together. Multiple parentheses can appear in one search string. A minus sign designates a word that must not be present in the document. In Normal Mode, the MetaCrawler reports results immediately after retrieval from the remote search engines. In Verification mode the MetaCrawler loads and verifies each reference to ensure the validity of the data.