Technology related to an activity feed service is disclosed. In one example of the disclosed technology, a method can include receiving updates to activity streams, where a respective activity stream indicates an engagement of a respective user with applications executing on a respective client device connected to a network. The different activity streams associated with a particular user can be merged to generate a merged activity stream associated with the particular user. The different received activity streams can correspond to different respective client devices. The merged activity stream associated with the particular user can be transmitted over the network.