New Bill to Mandate Captions for Web TV http://bit.ly/dawU17
First there has to be a commission set up to determine the time scale for implementation, and it only applies to material that has first been broadcast somewhere else. Since broadcasters mostly have to close caption for broadcast, the source material will be available.
This would be a burden if it were ever extended to original “web TV” (whatever that is).
But if it is ever mandated, then the Universal Subtitles Project might be the solution.