31. A non-transitory computer-readable storage medium tangibly storing thereon computer-executable code, that when executed by a processor, perform steps comprising: receiving crawling data from a crawler crawling a content preview source; extracting, in connection with crawling the content preview source, data and a link from the content preview source, the link comprising a link to a target document, the data to be used to create a content preview document previewing the target document, the target document containing content being previewed by the content preview source; creating, in connection with crawling the content preview source, the content preview document using the data extracted from the content preview source, the content preview document being different from the target document and the content preview source, the content preview document being created without using the target document; and making the created content preview document available for searching by a search engine in an index prior to the target document being made available for searching by the search engine in the index.
31. A non-transitory computer-readable storage medium tangibly storing thereon computer-executable code, that when executed by a processor, perform steps comprising: receiving crawling data from a crawler crawling a content preview source; extracting, in connection with crawling the content preview source, data and a link from the content preview source, the link comprising a link to a target document, the data to be used to create a content preview document previewing the target document, the target document containing content being previewed by the content preview source; creating, in connection with crawling the content preview source, the content preview document using the data extracted from the content preview source, the content preview document being different from the target document and the content preview source, the content preview document being created without using the target document; and making the created content preview document available for searching by a search engine in an index prior to the target document being made available for searching by the search engine in the index. 37. The non-transitory computer-readable storage medium of claim 31 , further comprising: using at least a portion of the extracted data to present the target document as part of search results generated by the search engine in response to a search query.