An information processing system comprising a first information processing apparatus operated by a user, the first information processing apparatus comprising: a display processing section adapted to display on a screen information indicating a game that is played at the moment on a second information processing apparatus by another user, the second information processing apparatus being different from the first information processing apparatus; and a transmission section adapted to send a viewing request for viewing the game via a network to the second information processing apparatus, wherein the display processing section is adapted to display in a predetermined area of the screen either a first operation button for sending a viewing request to the second information processing apparatus or a second operation button for acquiring game image data of the game from a server connected via the network to the first information processing apparatus and the second information processing apparatus, wherein the display processing section displays the first operation button when no game image data is sent from the second information processing apparatus to the server and displays the second operation button when game image data is sent from the second information processing apparatus to the server; the information processing system further comprising the second information processing apparatus that is operated by the other user, the second information processing apparatus comprising: an acceptance section adapted to accept game operation information from the other user; and a sharing processing section adapted to display a screen for selecting a first mode of delivery in which the game image data is sent from the second information processing apparatus to the server and a second mode of delivery in which the game image data is sent through peer-to-peer connection from the second information processing apparatus to the first information processing apparatus, wherein when the first mode of delivery is selected, the sharing processing section sends an invitation message to one or more other users who have sent a viewing request, and when the second mode of delivery is selected, the sharing processing section is configured to send an invitation message only to the user of the first information processing apparatus. a display processing section adapted to display on a screen information indicating a game that is played at the moment on a second information processing apparatus by another user, the second information processing apparatus being different from the first information processing apparatus; and a transmission section adapted to send a viewing request for viewing the game via a network to the second information processing apparatus, wherein the display processing section is adapted to display in a predetermined area of the screen either a first operation button for sending a viewing request to the second information processing apparatus or a second operation button for acquiring game image data of the game from a server connected via the network to the first information processing apparatus and the second information processing apparatus, wherein the display processing section displays the first operation button when no game image data is sent from the second information processing apparatus to the server and displays the second operation button when game image data is sent from the second information processing apparatus to the server; the information processing system further comprising the second information processing apparatus that is operated by the other user, the second information processing apparatus comprising: an acceptance section adapted to accept game operation information from the other user; and a sharing processing section adapted to display a screen for selecting a first mode of delivery in which the game image data is sent from the second information processing apparatus to the server and a second mode of delivery in which the game image data is sent through peer-to-peer connection from the second information processing apparatus to the first information processing apparatus, wherein an acceptance section adapted to accept game operation information from the other user; and a sharing processing section adapted to display a screen for selecting a first mode of delivery in which the game image data is sent from the second information processing apparatus to the server and a second mode of delivery in which the game image data is sent through peer-to-peer connection from the second information processing apparatus to the first information processing apparatus, wherein when the first mode of delivery is selected, the sharing processing section sends an invitation message to one or more other users who have sent a viewing request, and when the second mode of delivery is selected, the sharing processing section is configured to send an invitation message only to the user of the first information processing apparatus.