Here are some of the spots we did for Infor through Agency PJA with Steve Brodner.
Most of these are created to be .swf files. The media buy is primarily for targeted websites (like the NY Times, Business Week, Forbes, etc). A major component of the media buy is bandwidth -file size.
These files need to be anywhere from 18k to 32k. Some more complex pieces, like expandables or page take overs have larger sizes.
You can imagine the difficulty of fitting information, art and animation in those small files. A lot of compromises need to be made (mostly in art and animation).
In the above spot, we redraughted and repainted Brodner's artwork in Flash.
Below, we were working strictly under time/budget constraints and animated Brodner's illustration in AfterEffects.