1. A method comprising: identifying, by a social networking system, a content object with which a first user of the social networking system has interacted; associating, by the social networking system, a keyword phrase with the first user, wherein the keyword phrase is associated with the content object; and determining, by the social networking system, a mutual interest for the first user and a second user of the social networking system by identifying a match between the keyword phrase associated with the first user with a keyword phrase associated with the second user.