banners
Macromedia Flash 2 gives you the ability to easily create banners that can have complex animations and interactive buttons that link to more than one destination. Banner dimensions on different sites vary, but with the scalability of Flash 2 animations, you can resize the banner to fit the required dimensions by simply changing the width and height in the html only.
 

 
If you were to create the banner ad above, using conventional gif animation, the file could easily reach sizes of 200k and above, and would still require extra scripting to add the interactivity of the button.

With Macromedia Flash 2, the animated, interactive banner shown is under 10k.