4. The computer-implemented method of claim 1 , wherein: the received textual message includes a typing timestamp corresponding to a time that the received textual message was initiated by the sender user; determining the insertion point for the received textual message is further based on the typing timestamp.
6. The computer-implemented method of claim 4 , wherein the time that the received textual message was initiated by the sender user comprises a modification typing time at which the sender user began inputting a portion of the text content after deleting a previously input portion of the text content.