The present invention relates to a home appliance which can communicate with an outside of the home appliance, an online system including the same and a method for using an online system. According to embodiments of the present invention, a home appliance, an online system and a method for using an online system may be provided, each including a WiFi communication module mounted or connected to the home appliance for supporting a setting mode for making communication connection and a use mode for enabling communication, and a particular input unit provided to run the setting mode by user's selection, wherein the home appliance is changed to the use mode upon reception of SSID (Service Set Identifier; a name of a wireless LAN) information of an access point AP desired to access and user information required for registration of the home appliance through an external terminal after access to the setting mode through the external terminal provided separate from the home appliance.