Web services for instant messaging?

I’ve been interested in
Instant
Messaging and Presence
for some time now. A number of protocol
groups were spawned from the IMPP effort including
XMPP,
an XML based protocol that is the core for the
Jabber project.

Now, separately, an array of

specifications
have been written for web services, which are
fundamentally about exchanging messages with support for security,
reliability, addressing, routing, and subscriptions amongst other
things; in fact, most of the things in the requirements document
for IMPP RFC
2779
. Once all the tools support for these specifications
appears, it would be interesting to see how little code would need
to be written to construct an interoperable IM protocol. In the
meantime,

Bruce Williams has a blog post describing the WS-Eventing
specification
.