I've been working with SAML-based identity federations for a bit over four years now. For most of that time, it's been obvious that after basic federations like the UK federation and InCommon were up and running in production, the next big question would be how to break out of the "federation of my close friends" model. I've spent the last couple of years bending ears at conferences with my own particular views about how this might be done.
Impromptu in-person rants of that kind are very useful for finding out whether ideas have any appeal to other people at all, but I've felt for a while that something more coherent might be useful. I've therefore put together Some Notes on Metadata Interchange as a personal position paper on this area.
snomi-v2.pdf is the current version of the document;
snomi-v2-diff.pdf is the same document with change bars from the previous version. This means you can deduce what V1 looked like if that's of interest.
I very much welcome comments and discussion on this document. If you'd like to, you can leave a comment here (if you don't have a TypeKey account, there will be a delay before it's published) or post on your own blog or just send me e-mail.
Some disclaimers: This document does not represent the official position of any organisation or group, nor is it an attempt to describe any consensus view; it's purely a personal summary. It's not a collaborative document, except in the sense that if you change my mind I'll change the text.
I expect this document to change fairly often over the next few months; hopefully, some consensus-building (and even specification-building) efforts can be budded off from it when that seems appropriate; they will probably be hosted elsewhere.