1. An information-processing system comprising: at least one processor; and an input device configured to acquire one or more items of posting information posted in connection with an application, the at least one processor configured to: display the one or more items of posting information acquired by the input device on a display; and execute, in response to a predetermined input operation performed by a first user while the one or more items of posting information are displayed on the display, the application based on additional information indicative of an execution condition of the application.