Collective intelligence. Think of how Wikipedia works, how Amazon harnesses user annotation on its site, the way photo-sharing sites like Flickr are bleeding out into other applications... We're entering an era in which software learns from its users and all of the users are connected.
I said a long time ago that Foursquare can make cities better. You have these augmented realities like Foursquare and Twitter and Facebook that provide these virtual nodes and instant feedback from anywhere, adding annotation around a physical places.
The economics of television syndication and DVD sales mean that there's a tremendous financial pressure to make programs that can be watched multiple times, revealing new nuances and shadings on the third viewing. Meanwhile, the Web has created a forum for annotation and commentary that allows more complicated shows to prosper, thanks to the fan sites where each episode of shows like 'Lost' or 'Alias' is dissected with an intensity usually reserved for Talmud scholars.