Quantum entanglement is a subtle nonlocal correlation among the parts of a quantum system that has no classical analog. Thus entanglement is best characterized and quantified as a feature of the system that cannot be created through local operations that act on different parts separately, or by means of classical communication among the parts. One application of shared entanglement is a novel quantum communication protocol called quantum teleportation. To teleport a qubit (quantum bit) the receiver needs to receive two classical bits in order to recover the perfect replica. This protocol has been convincingly demonstrated in the laboratory.