Examples of a method and system for collaborative and private sessions are provided. In some aspects a collaborative shopping session including a first user and one or more other users is established. The establishing of the session including displaying a common interface for the collaborative shopping session at respective computer systems of the first user and each of the one or more other users. A side session is initiated for a second user, the side session having a different interface in which activity within the side session by the second user is not shared with the first user or the one or more other users of the collaborative shopping session. A determination, based on one or more merge criterion, of whether to merge the side session with the collaborative session is made; and the side session is merged with the collaborative session based on the determining.