I think we can all see how wonderful email is because of its interoperability and many of us wish IM had that. When Google announced XMPP federation, it felt like it could be the start of something better. It wasn't. Microsoft, AOL, and Yahoo didn't play along and even big third parties that used XMPP wanted to keep a walled-garden. But when Google kiled federation, it was a blow (at least to me). It meant that it wasn't going to happen. As long as Google was federating, there was that glimmer of hope that things might change. Maybe some startup will be open and awesome and it will kick-off change once people see how interoperability makes things great like email. Maybe even Microsoft or Yahoo would switch and it would pressure others creating a cascade. Today, even if Yahoo decided "open is the way to go for IM," they don't have Google already there. There had always been the possibility that someone big would join Google's openness. There isn't that possibility now.

I don't think it's hard to argue that things that are universal are better in a lot of circumstances. I can call anyone via phone number, I can email anyone via their email address. It's awesome. With something like Skype, I can only connect with Skype users. That's less great. Not only do I have to use Skype, I have to convince others to use it as well. People have to buy into Skype. When I switched to Gmail early on, it didn't matter if others didn't use Gmail. If something new and great comes along in the IM space, it likely won't get traction because of the network effects. I know that one can point to counter-examples. That isn't the point. The point is that users should be able to use and migrate to better services. The openness of email allowed Gmail to thrive with a low cost of switching.

I don't blame Google for going closed, but it is sad. It extinguishes some of the hope for something truly better. And it's sad when the champion of open throws in the towel on it. I'm not trying to canonize Google, but they have pushed for a decent amount of openness on the internet and when they've given up on open IM, it's hard to imagine someone else (who is big and influential) picking up the cause.