(pun title intended)
Tags* are Frameworks for Describing Resources...
It's gonna happen, oh it's SO gonna happen.
Actually, it's happening now.
It's not the big software companies, it's not the big media companies. It probably won't follow any current specifications, but I hope it will at least not blindly ignore them.
Baby steps, baby steps.
We begin with the primordial flat tag soup. Then out of the soup will crawl the soft hierarchies of community maintained folksonomies: loosely arranged molecule clusters of communities of usage. When the APIs mature, blood flow can commence, feeding a new organism. Small pieces loosely joined, indeed...
*or rather the systems we build that utilise tags. ;)