Google Talk is an interesting case; it was great having non-technical friends use a federated system (obviously they didn't know that, nor do they need to know

Google Talk is an interesting case; it was great having non-technical friends use a federated system (obviously they didn't know that, nor do they need to know that; this is one of the big problems with most small XMPP-based services, they only focus on technical people and use federation as a marketing point), but it was aweful dealing with, eg. Google refusing to follow certain standards, refusing to do TLS over S2S connections, etc. sigh indeed.