1. A computer implemented method, comprising: accessing a mapping document that represents an organization of related network-accessible documents within a website, at least some of the network-accessible documents whose organization is represented by the mapping document being mobile content; receiving an indication that at least some of the network-accessible documents whose organization is represented by the mapping document are mobile content; selecting, based on the indication that at least some of the network-accessible documents whose organization is represented by the mapping document are mobile content, a mobile content crawling mode to crawl the network-accessible documents of the website that are mobile content; crawling the website based on the mapping document to obtain information from the network-accessible documents, wherein the network-accessible documents that are mobile content are crawled in the mobile content crawling mode; adding the information from at least some of the network-accessible documents to a search engine index; receiving a search request from a mobile device; and transmitting search results to the mobile device, the search results responsive to the search request and identified at least in part using information in the search engine index.