In 1993 alt text was added to the HTML specification. Someone then posted an idea: A library where people could store and look up alt text for frequently used images. I've lost the post, and no one else that I can find has talked about it since.
I believe that the time is now, but I can no longer be who. As I announced yesterday, I am closing down the alt-text.org project, but others have expressed interest in carrying the project forward.
(cont)