USB 2.0 has been the standard connection for all external devices and peripherals almost since its release in 2000. Many users have switched to other types of data interfaces (such as Firewire 800) to transfer large amounts of data in a short time.
Super Speed USB 3.0 was specifically designed to address the speed problem by adding a 4th transfer mode on top of the existing 3. This allows USB 3.0 enabled devices and computers to take full advantage of Super Speed, but also connect without issue to older USB 2.0 and 1.1 devices. The new transfer mode increases the maximum USB transfer rate from 480MB/s to 5,000MB/s (5GB) and still maintains compatibility with older devices and systems.
USB 3.0 accomplishes its massive speed increase with the addition of 5 more wires. The creative part is how the USB Organization fit these extra 5 wires into the existing USB 2.0 connectors. USB 2.0 and 3.0 "A" connectors are interchangeable, the extra 5 pins near the front being the only major change.
Please feel free to view additional USB 3.0 information that includes images of cable and port comparisons at the following links: