AttentionTrust - Dan Gillmor's nonprofit dedicated to ensuring attention rights.
Nice idea, but I honestly don't think this is really necessary. If Media 2.0 is decentralized, it should be a relatively efficient market. This means that attention rights should be plastic enough that consumers can trade them where and when they see fit.
I think this would have been a great idea in a mass media world, where attention is effectively oligopolized because of the natural monopoly dynamics across media markets (viz, local papers, radio, etc) which led to nasty dynamics like ad time hypergrowth.