1. A method comprising; receiving, by a system, a user identifier corresponding to a user, the user identifier having an associated first timing information; receiving, by the system, information about a stroke generated on a whiteboard, the stroke having an associated second timing information generated independently of the first timing information; determining, by the system, whether a correlation exist between the user identifier and the stroke based on comparing the first timing information and the second timing information; generating, by the system, information associating the user identifier with the stroke based at least in part on the comparison; and storing, by the system, the association information.