Oh joy!
The WS-MetadaExchange specification has been updated. You can find the new spec here: http://specs.xmlsoap.org/ws/2004/09/mex/WS-MetadataExchange.pdf.

Notable differences:

  • The use of specifications from the WS-Management suite, namely WS-Transfer. Now the first method of retrieving metadata is treating them as WS-Transfer resources
  • The chance of embedding metadata directly in endpoint references
  • The request-response protocol for metadata retrieval is still there, but is now optional
  • The bootsrap of the metadata retrieval operation is now explicitly addressed (and the decision of forcing mex endpoint on HTTPS in CardSpace falls squarely in that domain, I'd say)

In general, the idea of representing everything as a resource holds tremendous potential for managing the service; while the spec does not mandate it (everything revolves around Get), you may think of using WS-Transfer's Put for actually pushing info to the services under your governance.

Hopefully in the next days I'll find more time to get an deeper look to it. Check it out :)