The problem: Discover information that email@example.com wants to publish to the world; things like their preferred identity provider, their public avatar, public contact methods, etc. Same mechanism should basically work for firstname.lastname@example.org or http://example.org/joe, no wheel reinvention.
The Webfinger session at the last IIW was quite productive in the sense that it produced a long list of open issues that need resolution. The whiteboard snapshot to the right (stitched together thanks to @factoryjoe) shows the list, albeit in low res form. Translating the notes, and giving my takes:
Starting assumption : Domain owners need to play along. We're not trying to handle the case where email@example.com wants to be discoverable, but doesn't control example.org and the domain owner doesn't want to implement discovery. Open Issues
Location of host-meta data: Older spec calls for this to be at /host-meta for every domain; Mark Nottingham has updated his proposal to create a /.well-…