Next Generation Flash
The world's first AI. (Auto Intelligent) Bounce Flash*, the 470EX-AI is capable of automatically selecting the optimum flash bounce angle in AI. Bounce Full Auto Mode whereas the AI. Bounce Semi Auto mode automatically retain a user-defined bounce angle whenever the camera changes orientation. The large LCD screen and selection dial enables easy viewing and adjustment. With a high degree of lighting, 470EX-AI is capable of covering a wide range of subjects and distances.
Guide Number: 47
Automatic Flash Distribution with AI. (Auto Intelligent) Bounce Technology
Supports wireless communication via optical transmission for multiple flash photography
Design
The 470EX-AI Speedlite have the capability to adjust itself based on the distance and exposure information from the camera for the best possible angle to bounce the flash. 
The speedlite could also maintain the direction and angle of bounce in both horizontal and vertical orientation.
 
Full Auto Mode on 470EX-AI
The light bounced off the ceiling to provide a soft over light and combined with some fill-in that gives flattering results.
High ISO without Flash
Using only available light alone could provide insufficient depth and may introduce noise when using higher ISO range. 
Direct Flash
Straight on light is harsh and is often less flattering.
A simple double press on the shutter button of you camera and the 470EX-AI Speedlite would automatically adjust its flash head to the correct angle and direction according to the camera orientation.
Not only does the 470EX-AI Speedlite automatically to adjust itself for ceiling bounce, it works the same for wall bounce as well!
Different angle for a different look
Designed with advance users in mind, the 470EX-AI allows you to manually adjust the speedlite bounce angle in semi auto mode.  
Here are the some samples of how a different angle would have different results.