23. The computer-implemented method of claim 21 , wherein grouping the first question and the plurality of questions in one or more groups further comprises: based on comparing the first question to the plurality of questions, determining that the first question and a second question of the plurality of questions have a similarity that is greater than a threshold; and based on determining that the first question and the second question of the plurality of questions have a similarity that is greater than the threshold, grouping the first question and the second question in a group of the one or more groups.
21. A computer-implemented method, comprising: collecting highlights of a digital work received from a plurality of digital work presentation devices wherein the highlights of the digital work include a first highlight entered to highlight a first passage; collecting questions crafted by one or more users, wherein each of the questions pertains to a corresponding highlight of a corresponding passage of the digital work, wherein the questions include a first question pertaining to the first highlight to highlight the first passage; storing the questions in association with the highlights to which the questions pertain; comparing the first question to a plurality of questions that pertain to highlights of the first passage, wherein comparing the first question to the plurality of questions further comprises comparing one or more phrases of the first question to the plurality of questions that pertain to the highlights of the first passage; and grouping the first question and the plurality of questions in one or more groups based at least in part on the comparing the first question to the plurality of questions.