1. A method of collaborative focused crawling of documents related to multiple focus topics on a network, the method comprising: selectively prioritizing the documents to crawl based on a set of rules; fetching prioritized documents from the network; for each fetched document, determining whether the fetched document is relevant to any of the multiple focus topics; crawling the fetched document that matches any of the multiple focus topics; and further crawling out-links on the fetched document based on an assumption that if the fetched document is of interest, the out-links are also of interest.