Google and various other Silicon Valley entities should create a Public Domain fund. Basic idea is that you submit some creative work (a song, image, etc.) and through the magic of up-down voting, the top X entries win some Y dollars. Only catch is that if you take money from the fund, your work must now be in the public domain.
A large number of people and groups depend on there being a robust public domain (or at least things easily redistributable via Creative Commons) — from lip dubs to remixes to fan fiction to mere inspiration, a substantial amount of creative expression takes the form of a derivative work. Whenever I feel the need to Photoshop (or GIMP) something together, I often spend a lot of time on Google Image Search or Flickr looking for source material. I imagine I’m not alone. Much of the derivative work out there gets by on fair use, but there’s definitely a good chunk of it doesn’t (or hovers in some gray area).
Furthermore, obtaining licensing and permissions from the original right holders is a tremendous hassle. There’re legal documents to be signed, dollars to be transferred, and hours to be wasted while you wait for someone to respond to your e-mail. Furthermore, the market value for a lot of these mash-ups is uncertain and probably not worth any licensing fee. More often than not, I’d bet that the creators of derivative works do one of two things: (1) give up on the current project or (2) use the source material without permission.
These derivative work creators would benefit from a large body of public domain works available for use. Now I’m not saying there isn’t already stuff out there. I certainly am usually able to find what I need given enough time, but it’d definitely make things a lot easier if public domain / less restrictive licensing were the norm. A Public Domain Fund would provide an economic incentive for creators to use less restrictive licensing.