"A virtual private Network (VPN) extends a private network across a public network, such as the Internet. It enables a computer to send and receive data across shared or public networks as if it were directly connected to the private network, while benefiting from the functionality, security and management policies of the private network. A VPN is created by establishing a virtual point-to-point connection through the use of dedicated connections, virtual tunneling protocols, or traffic encryption."
Between Wi-Fi spoofing, Honeypot attacks, and Firesheep, public networks really are cesspools. But if you're working remotely and need to access sensitive data on your company's private servers, doing so from an unsecured public network like a coffee shop Wi-Fi hotspot could put that data, your company's business, and your job at stake.
VPNs, or Virtual Private Networks, allow users to securely access a private network and share data remotely through public networks. Much like a firewall protects your data on your computer, VPNs protect it online. And while a VPN is technically a WAN (Wide Area Network), the front end retains the same functionality, security, and appearance as it would on the private network.