11. A system comprising: one or more processors; memory accessible by the one or more processors; a content receiving module, stored in the memory and executable on the one or more processors, to receive a content item associated with a content source, the content item including one or more approved portions that have been approved by a publisher for providing as a search result; a text extraction module, stored in the memory and executable on the one or more processors, to identifying one or more approved portions of an electronic book that have been approved by the publisher for providing as a search result, extract the one or more approved portions from the content item received from the content source to form extracted textual content, and create a digital sample for the content item, wherein the digital sample includes the extracted textual content from the content item, an indication of a type of the content item and a content item identifier that identifies the content item; a text selection module, stored in the memory and executable on the one or more processors, to receive an indication that indicates that a user has selected text displayed via a display device of a computing device; a search component, stored in the memory and executable on the one or more processors, to search for the selected text within the digital sample; a result mapping module, stored in the memory and executable on the one or more processors, to receive search results obtained by the search component that includes a results identifier associated with the search results, and an associated text string, map the results identifier to the content item identifier, determine a location of the associated text string from within the content item based at least in part on the results identifier, and convert the associated text string to a format for presentation; and a service module stored in the memory and executable on the one or more processors, to provide the associated text string to the computing device.
11. A system comprising: one or more processors; memory accessible by the one or more processors; a content receiving module, stored in the memory and executable on the one or more processors, to receive a content item associated with a content source, the content item including one or more approved portions that have been approved by a publisher for providing as a search result; a text extraction module, stored in the memory and executable on the one or more processors, to identifying one or more approved portions of an electronic book that have been approved by the publisher for providing as a search result, extract the one or more approved portions from the content item received from the content source to form extracted textual content, and create a digital sample for the content item, wherein the digital sample includes the extracted textual content from the content item, an indication of a type of the content item and a content item identifier that identifies the content item; a text selection module, stored in the memory and executable on the one or more processors, to receive an indication that indicates that a user has selected text displayed via a display device of a computing device; a search component, stored in the memory and executable on the one or more processors, to search for the selected text within the digital sample; a result mapping module, stored in the memory and executable on the one or more processors, to receive search results obtained by the search component that includes a results identifier associated with the search results, and an associated text string, map the results identifier to the content item identifier, determine a location of the associated text string from within the content item based at least in part on the results identifier, and convert the associated text string to a format for presentation; and a service module stored in the memory and executable on the one or more processors, to provide the associated text string to the computing device. 12. The system of claim 11 , further comprising a results filtering module, stored in the memory and executable on the one or more processors, to receive filtering criteria indicating a type of the content item in which to search for the selected text.