If you use your Mac in multiple locations, such as at home, in the office, and on the road, chances are you'll use many different networks, each with its own settings and configuration requirements.
Screen shot courtesy of Coyote Moon, Inc.
For example, you may use a secure wireless network at home and a hard-wired Ethernet connection at the office. If you stay at a hotel, you might have a wireless or wired connection, depending on the hotel. No matter what type of network is available, most Mac users open System Preferences and tweak their network settings in order to make a connection.
If you move around often, that method of connecting can get tiresome. To save time and aggravation, you can use OS X to create multiple network profiles. Your Mac will then automatically match the current network connection to one of your network profiles and automatically set itself up, with no intervention on your part.