Example implementations are directed to a method of controlling contributions to a communication stream. An example implementation includes detecting a request from a user to add a data item to a communication stream of a channel, analyzing the data item in view of the communication stream to determine a relevancy score for the data item; and providing a control interface for the request based on the relevancy score of the data item. For example, the control interface can include an audience report, a notification, a previous post link, an alternative channel recommendation, a private message invitation, or a proceed to post command.