An information processing system according to an aspect of the present invention has an acquisition unit for acquiring, from a plurality of terminal apparatuses, operation information signals indicating operations performed for the terminal apparatuses by users. The information processing system has a specification unit which uses the plurality of operation information signals to specify either a plurality of terminal apparatuses of interest for which the time difference among terminal apparatuses at the timing when a specific operation was performed is within an allowable time difference, or a plurality of users of interest that operate the plurality of terminal apparatuses of interest. The information processing system has an output unit for outputting a result corresponding to the specification result from the specification unit.
