Awesome and scary: Mozilla Popcorn Maker

Heard about this on This Week in Google #172: Mozilla branches out into online video editing and remixing with Popcorn Maker.  The product allows you to layer other content over web video; imagine watching an interview and getting a live Twitter feed of the interviewee (and heck, why not the interviewer, too?), or Wikipedia articles or Google Maps relevant to the subject matter.  It seems to rely on the ability to link to all the content you use, including the video, but I suspect this could be a bit of a legal minefield for copyrighted material.  I could see this as an interesting collaborative tool for annotating lectures or other academic material.  It also has the potential for being used as digital graffiti, but since the original content and link shouldn't be affected, hopefully that won't be a major problem.  Definitely a product with a lot of potential in an awesome and possibly scary way; awesomely scary? Scarily awesome?