Interesting, I seem to recall an entirely different order of release. Blame it on personal bias (was already using XMPP at the time of Talk's release) and/or aging memory, I suppose.

I remembered it exactly the other way round and also wasn't sure. It's curious/disturbing that events barely over a decade past are difficult to google. 'What was the first gtalk client'. 'When was gtalk integrated into gmail'. 'When did gtalk get an OS X client'.