When Google Talk launched I remember being impressed that they chose an open format as their protocol. Google picked XMPP, better known as the Jabber protocol, rather than invent their own proprietary protocol. This was cool enough on its own. But what I didn't realize at first was that Google would go all the way and open up their servers to connect with the federated XMPP network at large.
Which got me to thinking: if Google really did open their network then any third party could run an XMPP server and talk directly to Google users and vice-versa. Even better, you could host your own XMPP server and then Gmail users could IM you directly -- perhaps even straight to your personal email address.
It was time to try that out on Unto.net.
First I set up a XMPP server on Unto.net. I experimented with wildfire (a Java-based memory hog) and ejabberd (written in Erlang of all things) before settling on jabberd 1.4 (nice simple C). All of those servers come with more features than I need; choice ultimately came down to a question of convenience.
I created an account for myself on the Unto.net XMPP server, disabled new user registrations, and opened a port to connect to the global network. To test the service I logged in to the Unto.net server with iChat and sent a test IM message to my Gmail address.
It worked! Picture below:
Since Google's IM network is hooked into the larger XMPP network you can chat to any Jabber user directly via Google Talk or from within Gmail. Or you can do what I did: run a public XMPP server for the same domain that hosts your email. Your friends already know your email address, so why not let them IM you there?
In other words, if you (on Gmail) and I (on Unto.net) exchange emails then you can click on "Chat" and start IM-ing with me -- even though my personal email account has no pre-established association with Gmail. And unless I'm mistaken, the Gmail interface will even show my name in your contact with a little green/orange/red/grey status dot next to it once we've chatted at least once.
If you use Gmail then please try inviting me to chat. Or even better; try setting up your own XMPP server on the same hostname as your email domain and you can do the same trick.
I've heard conflicting stories about whether or not Google will be able to interoperate seamlessly with AIM users via XMPP. (Yes, you can already bridge to AIM through your XMPP server, but that is not the same thing.) But imagine if AIM added a XMPP layer. Then you could IM cross-network, both to large and small servers. It is doubtful that either MSN (er, Windows Live) or Yahoo! will follow suit in the short term, though.
Like my enthusiasm for OpenID earlier this week, XMPP is an important step along the way toward service decentralization. When Google Talk launched I was just thrilled that they were using XMPP. That they are federating is potentially game changing.