A network. In a home or Business, you have a LAN (Local Area Network). These connect to the WAN (Wide Area Network), more commonly known as the World Wide Web.
The device allowing two computers to communicate with each other is... a router (or modem).
modem
A cross-over cable.
It allows computers to "talk" each other in network.
Network card
The motherboard is the brains of the computer. The motherboard is a large printed circuit board. It allows components to communicate with each other.
The basic protocol that allows all computers to interact on the internet is TCP/IP.
I'm pretty sure LAN's are a group of computers connected to each other through routers/modems or ethernet cables. The internet it similar to LAN's but instead of connecting to other computers close by, it connects to computers all around the world.
Network attached storage is a device that connects to a network of computers and allows for storage separate than on each computer. This is useful in many businesses because it allows each separate computer to have a way of backing up their files, and also access those files from each separate computer within the network.
The advantage is that you can hook things up all together. It allows different computers and technology to communicate with each other.
VNC stands for Virtual Network Computing. It is a graphics based system that allows computers to communicate with each other over a 'virtual' network. This means people can access their work computers at home, or their home computers at work.
Multi-threading is a programming model that allows computers to communicate with each other using the same resources, but work independently. This process became supported in the late 1990s.