Here's what I don't get about Google. A few years ago, they were one of the only players in the IM game, alongside MSN, AOL IM, ICQ... have you heard about any of these lately? Of course not, they're all dead. Talk was built on top of XMPP, an open protocol, which helped its popularity as third party clients could connect to it. Talk was also built in to gmail, and at the time that was revolutionary: A fast and light…
Facebook Chat went live 2008-04-06. Google didn't view them as a threat in messaging but a threat in social networking; they thought they had messaging in the bag with their 2008-09-23 release of Android 1.0, and their 2008-11-11 update to Google Talk which brought voice and video calling, and their 2009-03-11 acquisition of GrandCentral, which was soon rebranded an invite-only Google Voice. But Facebook kept growing and growing and it had an integrated chat on a website where people went to spend their time, instead of Gmail, where they went to manage email.
To combat Facebook on social networking, Google launched Buzz with aggressive auto-opt-in on 2010-02-09. Buzz fizzled and attracted controversy for its aggressive piggybacking on Gmail, so Google tried again with Google Plus on 2011-06-28. That was a better effort, and it included the features "+Messenger", a text chat, and the video chat "+Hangouts". By this point Facebook had more than 700 million active users, and won messaging handily; its lead was cemented by the acquisition of WhatsApp on 2014-02-19, as Google continued to flail about.
In a post of mine last year [2] (which includes an older revision of the timeline linked in [1]), I speculate that it was Facebook Chat that killed the mid-2000s chat networks of old like AIM, Yahoo Messenger, and WLM, rather than Google Talk or any particular missteps of those incumbent chat networks. For example, I was surprised to learn that AIM was present in the iOS App Store at launch -- of course, there were no push notifications at the time -- not until 2009-06.