Hi,
When I added my GoogleTalk it was when iChat 3 added Jabber abilities to iChat.
At that time there was no separate Google Add option.
You had to Select Jabber as the Add option and then Add your Google ID (and Password) and then after finishing the Set up you had to go to the Server Settings Tab and manually change the Server to talk.google.com
The reason for this is every other Jabber ID is the UserName@JabberServerName.com
So any app would strip the Username@ part away to use the Server name as the Jabber Server Name part.
As Google has two forms of Google Mail IDs then it would show googlemail.com or gmail.com as the server name.
As these two are the mail servers they don't work for the Jabber server.
More recently Google decided that SSL was not "good enough" for a login.
iChat, Messages and Mail all use SSL to login to Google.
You had to go to the Security settings at the Google Account page and enable "All Less Secure Apps".
I don't use their 2 Step verification and posts here seem to be mixed on whether it works with Messages.
Along the way Google have started Hangouts whilst also leaving Google Talk to continue.
A little while back (about six months) I was able to change to Hangouts and also return to using GoogleTalk.
This, from two years ago, suggests there was (is ?) a bridge between GoogleTalk and Hangouts
https://www.reddit.com/r/google/comments/1wo8vp/what_is_the_server_for_hangouts/
What is does not say is whether a Hangout ID can be used to login to GoogleTalk (A bridge would let you add Buddies with IDs from the other)
You could Video in iChat and Messages Mac to Mac (Not other Platforms)
You could Video in a Browser to Browser with a Google Video Plug-in.
You could not Video between a Browser Login and iChat or Messages (there is confusion in the Linked thread over this)
I searched the App Store for Google Hangouts and got several apps listed (I did not check which were iOS or Max OS types)
More recently my Google Account in Messages has changed to using this set up (Despite me changing it back).
It is not using SSL at all (Despite that being set at Google).
It is no longer using the talk.google.com server.
I "Googled" for Hangouts in Messages and this was the top hit
http://www.imore.com/how-use-google-hangouts-messages-app-your-mac
It looks good from the beginning (Although I dislike setting up things in Internet Accounts opposed to the apps themselves).
However the comments below that are less positive about it.
8:33 pm Saturday; May 28, 2016
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