article by: http://whatismyipaddress.com/mac-address
Whether you work in a wired network office or a wireless one, one thing is common for both environments: It takes both network software and hardware (cables, routers, etc.) to transfer data from your computer to another—or from a computer thousands of miles away to yours.
And in the end, to get the data you want right to YOU, it comes down to addresses.
So not surprisingly, along with an IP address (which is networks software), there’s also a hardware address. Typically it is tied to a key connection device in your computer called the network interface card, or NIC. The NIC is essentially a computer circuit card that makes it possible for your computer to connect to a network.
An NIC turns data into an electrical signal that can be transmitted over the network.