My idea is that a meta-database dedicated to storing information about files should be the basis for user-submitted content.
This information would include include comments (stored and editable by the commenting user), and the file’s URI.
The comments could be made in a new standard format to give an impression of how they should be interpreted.
The interpreter program (not necessarily affiliated with the meta-database) would make comments user-readable, and allow easy commenting.
Person A wants to post a video file.
The interpreter asks them: for the file’s location on their hard disk; for a description of the file; if it’s ok to use the computer’s video processing software to make lower-quality versions.
Then the interpreter makes the file public. It submits the URI to the meta-database, along with a comment including the description and lower-quality URIs.
Someone using the interpreter could go to the file’s URI, and the interpreter would show a webpage displaying the video and relavent information from the meta-database.
The interpreter would recognise that the first comment contains a tag, and was uploaded by the same MPID as the file, and would therefore display the contents of the tag as that of a YouTube description. This recognition would also enable YouTube-ifying existing videos.
The interpreter would recognise that the first comment also uses a tag to store the lower-quality versions, and would include them in the HTML5 player (I don’t know if this is how HTML5 works).
The other comments would be displayed as comments, preferably in a Reddit-like layout. Not sure how upvoting/downvoting would work.
Executable file example:
A site offers a download of an executable file.
Someone sees that this file is dangerous, and comments a summary of this in the meta-database.
Another user downloading the file (via a comment interpreter) would see this warning as they download the file.
Like the YouTube one without video.
This could be linked to files describing the albums and artists to allow better categorisation.
An opt-in user-tracking system could be used to determine related sound files to provide suggested tracks.
Meta meta example:
Someone finds the URI of a user comment, and then comments on it.
(I’m not a programmer)