IPTC and photo metadata

I am not surprised to learn that the International Press Telecommunications Council is working on photo metadata with Adobe.

I wonder if there's value in coming up with a standard shared metadata structure for consumer photo applications. Right now, flickr is the closest we've come, but what if flickr wrote the viewing data, comments data, etc, all back onto the file itself, instead of keeping it in their own databases. Open source metadata is the idea here.