As I've been delving deeper into bitmap caching and game optimization I keep running across Blitting (BLIT, bitBlit) and Double Buffering.
I think I finally have a good grasp on both after using more resources from 8BitRocket as well as Jesse Warden's blog post which can be found here.
Here is the brief low-down:
Blitting is taking many bitmaps and combining them into 1 bitmap. Jesse (and wikipedia) use pac man as an example. Instead of having a sprite or bitmaps for each ghost, dot, wall, and pac man himself, the game actually is only displaying 1 bitmap. The rest of the objects are just having their pixels copied onto the main bitmap. This dramatically improves performance since flash no longer has to render all of the multiple movie clips.
Double Buffering is using 2 bitmaps to display the entire game. 1 bitmap is being altered in the background while the other is being shown to the user. Once the first one is finished being altered it will swap with the one being shown. This prevents flickers from occurring on the screen. 8BitRocket makes an interesting suggestions of just using 1 bitmap and locking it while you make all the transformations and then unlocking it before you call the update screen event. They call in the "poor man's double buffer".
Not sure if I will be using either of these techniques yet in the upcoming side scroller, but at least now if I don't use them I will understand them and have a reason for not using them.