document: Efficient query subscription processing for prospective search engines Current web search engines are retrospective in that they limit users to searches against already existing pages . Prospective search engines , on the other hand , allow users to upload queries that will be applied to newly discovered pages in the future . We study and compare algorithms for efficiently matching large numbers of simple keyword queries against a stream of newly discovered pages .
doc_bio_tags: O O O O O B I O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O