Ad Weight

Ads need to be assigned a "weight" based on the amount of interactivity, file size, and height/width. With the lighter ads floating to the top and the heavier ads sinking to the bottom.

The reasoning behind this is that although rich media advertising tends to me more effective, it also tends to be more intrusive. This intrusiveness isn't inherently bad, but it needs be a lower priority than the content the user is requesting. By allowing lighter ads to float to the top, they can be seen without overpowering the content. The rich media ads will be seen no matter what, so they can fall lower on the priority list.