I guess its a trade-off?
I consume a lot of video and audio content, but I'd get by with a transcription of podcasts and informational videos.
The info that's really important to me is predominantly text: Health related stuff, techniclal/build guides, nutrition, general encyclopaedia stuff. Again, most of it is blogs, podcasts, journals. I don't think it's unrealistic (in terms of resources) to build and maintain a bounded index of all of this and share signed versions with peers in Nostro/Vostro directory structure on a public key addressed home server. There could be an economic incentive for sharing perhaps?
This obvsly won't compete with huge centralised search engines, but I think it's probably true that after a certain volume of content, there's a diminishing return (in terms of value) the more that's indexed.
Appreciate your thoughts.