Humans have to tag the files, though. This is the same problem which kept the "semantic web" from going anywhere.
Humans have to tag the files, though. Only once, if done properly. Look at music tagging. A good system ought to have canonical tags for everything. User-created files could also have a lot of auto-generated tags too. I'm thinking along the lines of email address/URL origin, Exif metadata, source code tags (ctags/etags), keyword extraction from prose text (via machine learning models)... Beyond all that, though, woul…
Look at music tagging.
That has a high ratio of fans to content. That's when reputation systems work. Outside of popular culture, it doesn't scale.