[JDEV] Server Independent Accounts

[Michael Brown]

I was trying to convince a friend to change to Jabber a while back, and he
was telling me that Jabber wasn't really what he was looking for.  He is
trying to find an IM service that has accounts that are independent of the
server they are running on.

How it would work is this:

You are assigned a unique account name.  (Ok, coming up with unique names
can be tricky, but bear with me).  For arguments sake, lets say mine was
"Michael_S_Brown".  (Note there is no server as part of the address)  Now,
when someone sends me an instant message, something similar to an DNS lookup
happens, and my account is resolved to a particular server.  Say I am at
work at that particular time, it gets resolved to
Michael_S_Brown at mywork.com - however if I was connected from home, it may
resolve to Michael_S_Brown at myisp.com .

One of the advantages of this, is that if I change jobs, people don't need
to know that, and can still send messages to Michael_S_Brown.  They don't
care if it resolves to Michael_S_Brown at mywork.com or
Michael_S_Brown at mynewwork.com .  Likewise, if I change ISP's and I am at
home, it might resolved to Michael_S_Brown at mynewisp.com but people messaging
me neither know nor care that I have changed ISP's recently.

Having email addressed to a particular server was always a pretty lame idea,
although I'm sure the ISP's love it, because it makes it harder for users to
change to another service provider.  Think how hard it would be if your
website was tide to a particular server, and if you physically moved your
site to a different location you had to email everyone who might go to that
site and tell them "Sorry, but I have changed servers.  If you want to go to
http://www.mydomain.com now, you will have to remember to type
http://www.mynewdomain.com".  It's not very practical, but it is exactly
what we do with email addresses, and now Jabber addresses.

Anyway, my question I guess is:

Was anything like this considered in the early days of Jabber design?
If so, was it discounted for some reason?  Why?
If not, is there anyway to incorporate something like this into the current
Jabber spec?
(I suspect not - the best thing I can come up with is some sort of message
forwarding like bigfoot.com does for email).

Michael.