[metajack]

> In 2005 Google added XMPP support to Google Talk/GMail Chat and they were federated, but nobody federated back and they closed off its successor (Hangouts).

I don't think "lack of federation back" was a big driver in this decision. Everyone who used XMPP was able to chat with gchat folks and despite some weird changes Google made to their integration, it worked reasonably well. You didn't need to do anything special to federate with another XMPP server. It just worked like email does.

I expect either product complexity (like having to support non-gchat addressing which then requires full JIDs instead of short names) or de-prioritizing features that weren't directly driving their growth thesis were probably more relevant. Ie, why spend two engineers to fix integration concerns and deal with federation everywhere, when you can just retask those headcount onto some new feature that will drive growth.

[tapoxi]

I really mean that no other big chat service federated back. The global network of federated XMPP servers was dwarfed by Google's userbase. Maybe if AIM/MSN/Yahoo added an XMPP bridge they would have kept it.

[yepguy]

I seem to recall there was a brief period of time when gchat federated with both XMPP and AIM, and I was using Gajim to chat with users from both of those services without a bridge (or at least, the bridge run by Google/AOL was invisible to me).

[als0]

Wasn’t Facebook Chat a big one?

[prash_ant]

Yes: https://news.ycombinator.com/item?id=9266769

[Macha]

Was Facebook messenger ever _federated_ though, like GChat was? You could use an XMPP client with messenger, but you couldn't talk to people on other XMPP servers like you could with Google Talk, from my recollection.