1. A method comprising: by one or more computing devices, identifying, at a client device, one or more objects or references to the one or more objects embedded in a structured document displayed to a first user; accessing a social graph to determine if one or more second users having an association with the first user have accessed any of the one or more identified objects; and modifying, for at least one of the one or more identified objects, the structured document displayed to the first user to indicate that the at least one or more identified objects has been accessed by one or more second users.