1. A method implemented by a computer comprising at least one processor for providing controlled access to a document, the method comprising: receiving a search query; identifying a document responsive to the search query; identifying a plurality of search excerpts in the document, wherein a search excerpt is a portion of the document that satisfies the search query; accessing usage data describing how many times a plurality of users have accessed the plurality of search excerpts in the document, wherein the usage data indicates that the search excerpt has not been accessed by any of the plurality of users; and determining, based on the usage data, whether to present the search excerpt in response to the search query.