1. A computer-implemented method comprising: receiving, from at least one client device associated with at least one user of a content item, one or more annotations related to a content item; ranking portions of the content item based, at least in part, on a number of the one or more annotations that relate to a respective portion; selecting a ranked portion of the content item based at least in part on determining that a number of pages of the ranked portion does not exceed a predetermined preview amount of the content item; and sending content of the selected portion as a preview of the content item.