Hey Frank,
I see you chatted with one of our filmmakers about this. I commented this on his profile and wanted to share it with you too: I just want to let filmmakers who are curious know that we actually don't use stock footage anymore, unless we buy it outright. It's just to iffy even if it is in the public domain. One reason (among others) you often don't have the rights to redistribute content that's in the public domain. Hope that makes sense. If anyone has questions, please email me at emergingfilmmakers@howcast.com. Thanks!
Hey,
Good question. All stock footage is under a creative commons license from www.archive.org. It's an amazing site with tons of rights free stuf. I often use footage from the "Prelinger archive" in the video section. Hope that helps.
HeatherMenicucci