1. A computer apparatus for collaborative web search, comprising: a processor, a search engine, executed by the processor, the search engine producing an initial search result list in response to a query by a user of the search engine, and a list optimizer coupled to the search engine to receive the initial search result list and rerank pages on the list based on implicit endorsements of pages by the user of the search engine, the list optimizer forming and outputting a final result list from at least the reranked pages, wherein the list optimizer employs a last clicked heuristic to define endorsement of a page by the user, wherein the list optimizer is to further utilize pages endorsed by at least one of the user of the search engine and another user of the search engine in queries to the search engine in reranking the pages, the queries to the search engine being different from the first query by the user of the search engine.