Actually, in-video linked ads date back to the 80s

Mike Arrington has been stirring it about YouTube's new in-frame ads but this idea is something that dates back years, way back to the late 80s. In 1989 my colleagues Max Whitby, Nikki Barton and Chris Prior made a documentary with Douglas Adams called "Hyperland" looking at hypertext and the interlinked video future. Here's a snip where they explain 'micons':

What they went through back then to make all those overlaid animated video loops doesn't bear thinking about. I remember it involving Macromind Director and early 8-bit video capture cards and writing out to framestores one frame at a time...