1. An Internet appliance, comprising, within a single housing: (a) a first packet data network interface, configured to communicate with the Internet; (b) a second packet data network interface, configured to communicate with a local area network; (c) at least one data interface selected from the group consisting of a voice telephony interface, an audio program interface, a video program interface, an audiovisual program interface, a camera interface, a physical security system interface, a wireless networking interface, a device control interface, a smart home interface, an environmental sensing interface, or an environmental control interface; (d) a memory; and (e) a processor, for executing code stored in said memory for causing said processor to control a data transfer between said local area network and the Internet, and to define a markup language interface communicated through at least one of said first and second packet data network interfaces to at least one of (i) control a data transfer; and (ii) control a remote device, through said at least one data interface.