Interface for Sharing Posts About a Live Online Event Among Users of a Social Networking System

An external system (e.g., a website) is associated with an event and includes an interface that allows users to interact with streams of content associated with a social networking system. The interface allows a user to provide posts about the event via the interface, where the posts are displayed in the interface and also in a social networking interface on social networking system in connection with the user and other users associated with that user. The user can view, via the interface on the external system, posts from all users that are provided via the interface (e.g., everyone watching the event), thereby increasing the likelihood that the posts are relevant to the event. The user can also view, via the interface, posts from users associated with the user via the social networking system (e.g., friends of the user), regardless of where those are posted.