Abstract: Computer method and apparatus for collaborative web search operate in an intranet with non-existent or defective link structure. A search engine produces an initial search result list in response to a user query. A list optimizer reranks pages on the initial list based on implicit user recommendation or endorsement of pages. A last click heuristic defines user endorsement of a page. To form the final result list, the list optimizer scores each page according to reranking, a textual match (or information retrieval score) of the page with the query and an adjustment value.