As shown in FIG. 4, each client computing device 320 and 330 may be a personal computing device intended for use by a user 322, 332, and have all of the components normally used in connection with a personal computing device including a one or more processors (e.g., a central processing unit (CPU)), memory (e.g., RAM and internal hard drives) storing data and instructions, a display such as displays 324, 334, 344 (e.g., a monitor having a screen, a touch-screen, a projector, a television, or other device that is operable to display information), and user input devices 426, 436, 446 (e.g., a mouse, keyboard, touch-screen or microphone). The client computing devices may also include a camera for recording video streams, speakers, a network interface device, and all of the components used for connecting these elements to one another.

Although the client computing devices 320 and 330 may each comprise a full-sized personal computing device, they may alternatively comprise mobile computing devices capable of wirelessly exchanging data with a server over a network such as the Internet. By way of example only, client computing device 320 may be a mobile phone or a device such as a wireless-enabled PDA, a tablet PC, a wearable computing device or system, laptop, or a netbook that is capable of obtaining information via the Internet or other networks. In another example, client computing device 330 may be a wearable computing device, such as a “smart watch.” As an example the user may input information using a keyboard, a keypad, a multi-function input button, a microphone, visual signals (for instance, hand or other gestures) with a camera or other sensors, a touch screen, etc.