1. A computer-implemented method comprising: receiving, from a user client device, a hyperlink to send to one or more users via a communication system; acquiring a set of data from a target referenced by the hyperlink; storing at least a portion of the set of data on a server; analyzing the set of data to automatically generate a set of candidates for each of a summary and title of a preview for the hyperlink, wherein the preview provides a synopsis of content at the target referenced by the hyperlink; ranking the summary and title preview candidates based on relevance to the target referenced by the hyperlink, wherein the relevance is determined via analysis of positive and negative signals for each candidate, and wherein the analysis includes a comparison of content from at least one title preview candidate with content from at least one summary preview candidate; selecting a top ranked summary and title from the set of candidates; and transmitting, to the user client device, a preview candidate including the selected summary and title in response to receiving the hyperlink.