Suggesting Content for Discovery Based on User Interests and Authorship

An online system allows its users to posts content to the system and to see the content posted by other users of the system. The system helps users discover new content and sources thereof that may be interesting. For example, a first user expresses an interest in a content item and communicates that interest to the system. The system then identifies a second user who posted that liked content item and identifies content items in which the second user has communicated an interest. Based on this, the system selects one or more of the content items liked by the second user and provides the selected content items to the first user. The system may decline to send the content item to the first user if it was posted by a third user with whom the first user has already established a connection.