FLV white background Question

I’m trying to do some research into how Macromedia, and others in their showcase, manage to shoot video that appears to have no background, or in most cases (if not all) it is white. It gives the impression that the person they have filmed is in the flash movie without borders. For a good example check out:

http://www.macromedia.com/resources/business/rich_internet_apps/overview/

and of course their video showcase as well…

ANYWHO: Does anyone know how this is acheived? I’m not sure if it’s a green/blue screen they shot against and masked out, or if they used a white backdrop and high contrast to maintain the appearance of a ‘white landscape’. Any insight into the technique, or links, would be most appreciated! Thanks in advance!