An information processing system, comprising: authentication means for: receiving a user ID and a password input to a login page, the password being input as part of an operation performed in a password input field of the login page; identifying a password set in advance by the user and associated with the user ID, in account data stored in a data storage unit; and successfully authenticating the user when the password input to the login page is the same as the identified password; control information identification means for identifying control information, which is information different from the password set in advance by the user, and is based on content of the operation performed in the password input field with the input device, and determining whether to display information according to a private mode or according to a public mode based on the control information; publicly-displayable range identification means for identifying, for display in the public mode, a publicly-displayable range of information relating to the user based on the control information; and limiting means for limiting, in the public mode, a range of information relating to the user that forms a basis of a screen provided to the user so that the range of the information falls within the publicly-displayable range identified by the publicly-displayable range identification means, when the user is successfully authenticated by the authentication means, such that: in the private mode, links to pages introducing items or services identified by item IDs associated with the user ID in access history data and purchase history data are arranged in a region of the screen; and in the public mode, the items or services identified by item IDs associated with the user ID in access history data and purchase history data are not displayed on the screen. authentication means for: receiving a user ID and a password input to a login page, the password being input as part of an operation performed in a password input field of the login page; identifying a password set in advance by the user and associated with the user ID, in account data stored in a data storage unit; and successfully authenticating the user when the password input to the login page is the same as the identified password; receiving a user ID and a password input to a login page, the password being input as part of an operation performed in a password input field of the login page; identifying a password set in advance by the user and associated with the user ID, in account data stored in a data storage unit; and successfully authenticating the user when the password input to the login page is the same as the identified password; control information identification means for identifying control information, which is information different from the password set in advance by the user, and is based on content of the operation performed in the password input field with the input device, and determining whether to display information according to a private mode or according to a public mode based on the control information; publicly-displayable range identification means for identifying, for display in the public mode, a publicly-displayable range of information relating to the user based on the control information; and limiting means for limiting, in the public mode, a range of information relating to the user that forms a basis of a screen provided to the user so that the range of the information falls within the publicly-displayable range identified by the publicly-displayable range identification means, when the user is successfully authenticated by the authentication means, such that: in the private mode, links to pages introducing items or services identified by item IDs associated with the user ID in access history data and purchase history data are arranged in a region of the screen; and in the public mode, the items or services identified by item IDs associated with the user ID in access history data and purchase history data are not displayed on the screen. in the private mode, links to pages introducing items or services identified by item IDs associated with the user ID in access history data and purchase history data are arranged in a region of the screen; and in the public mode, the items or services identified by item IDs associated with the user ID in access history data and purchase history data are not displayed on the screen.