A computer-implemented method for negotiating a time and a medium for communications between users is described. The method is performed at a server including one or more processors and memory storing one or more programs. The method includes receiving a request from a first user to negotiate a time and a medium for communication with a second user. The request includes a plurality of acceptable mediums of communication. The method also includes generating a first notification based on the request. The first notification includes the plurality of acceptable mediums of communication. The method furthermore includes transmitting the first notification to the second user, and receiving a response to the first notification from the second user. The response indicates whether the second user has accepted one of the acceptable mediums of communication.