Network Card -10/100 Ethernet

Most systems today come standard with a built-in network card.  A standard computer network (the connection of multiple computers) runs at 100MBps (mega-bits-per-second).  Typically a category-5 cable that is used to achieve this speed.  Every computer on the network needs to have a network card, often referred to as NIC network interface card, or network adaptor.

Each computer is then connected to a hub or a switch that acts as the centralized unit that handles all of the network traffic.  Hubs and switches can be combined and linked to join neighboring networks, this is essentially how the internet began.

Analogy - The network card acts as a "translator" that allows your computer to "talk" to the others computers on the network.

History - Older systems used 10BaseT as the standard connection cable.  This cable looked like standard coaxial cable but could only achieve speeds up to 10MBps.  Once category-5 cable came out (which looks like a telephone cable) networks were able to achieve the higher 100MBps speed.  

Manufacturers - AOpen, Linksys, SMC, Netgear.

What You Are Looking For - There is nothing particularly special about what to search for. Your biggest factor is price.  A good network card costs about $25-30.