Marketing Sherpa debunks the idea that "rich media ads are hot" - ie. advertisers using them more and more. And they get bonus points for mentioning that they were one of the outlets promoting that idea 6 months ago. Here's data from a survey about rich media ads:
Dec 2003 Dec 2004
We do not spend on this 42% 39%
Increasing spending substantially 15% 11%
Got great rich media results 34% 34%
Got moderate results 38% 48%
Disappointing results 29% 18%
In this article, they claim that rich media ads (i.e. Flash and movies) usage isn't really growing very fast. They also have a list of "worst practices" around rich media ads. Definitely worth a read - but it's only "open access" until Apr. 9.