A method, comprising: at an electronic device having one or more processors, memory, a touch-sensitive surface, and a display: displaying a messaging user interface on the display, the messaging user interface including a conversation transcript of a messaging session between a user of the electronic device and at least one other user; receiving a first message within the messaging session from an electronic device that corresponds to another user included in the messaging session; in response to receiving the first message, displaying the first message in a first message region in the conversation transcript on the display while concurrently displaying, in an other message region in the conversation transcript that is distinct from the first message region in the conversation transcript, an earlier message in the messaging session; detecting a first input by a first contact at a location on the touch-sensitive surface that corresponds to a location in the first message region in the conversation transcript; in response to detecting the first input, an acknowledgement selection affordance at a location in the messaging interface that corresponds to the first message region, wherein the acknowledgement selection affordance displays a plurality of acknowledgement options (5014-1 - 5014-5); detecting a second input by a second contact at a location on the touch-sensitive surface that corresponds to a location of a first acknowledgement option in the acknowledgement selection affordance; in response to detecting the second input: applying the first acknowledgement option to the first message; and, transmitting information that causes one or more electronic devices that correspond to the at least one other user included in the messaging session to apply the first acknowledgement option to a corresponding first message in a conversation transcript that corresponds to the messaging session. at an electronic device having one or more processors, memory, a touch-sensitive surface, and a display: displaying a messaging user interface on the display, the messaging user interface including a conversation transcript of a messaging session between a user of the electronic device and at least one other user; receiving a first message within the messaging session from an electronic device that corresponds to another user included in the messaging session; in response to receiving the first message, displaying the first message in a first message region in the conversation transcript on the display while concurrently displaying, in an other message region in the conversation transcript that is distinct from the first message region in the conversation transcript, an earlier message in the messaging session; detecting a first input by a first contact at a location on the touch-sensitive surface that corresponds to a location in the first message region in the conversation transcript; in response to detecting the first input, an acknowledgement selection affordance at a location in the messaging interface that corresponds to the first message region, wherein the acknowledgement selection affordance displays a plurality of acknowledgement options (5014-1 - 5014-5); detecting a second input by a second contact at a location on the touch-sensitive surface that corresponds to a location of a first acknowledgement option in the acknowledgement selection affordance; in response to detecting the second input: applying the first acknowledgement option to the first message; and, transmitting information that causes one or more electronic devices that correspond to the at least one other user included in the messaging session to apply the first acknowledgement option to a corresponding first message in a conversation transcript that corresponds to the messaging session. applying the first acknowledgement option to the first message; and, transmitting information that causes one or more electronic devices that correspond to the at least one other user included in the messaging session to apply the first acknowledgement option to a corresponding first message in a conversation transcript that corresponds to the messaging session.