[jsejcksn]

Google’s past use of XMPP in an older iteration of its integrated Chat product (it was called Google Talk back then) is what first put this technology on my radar. In recent years I’ve been using Matrix instead — which has been covered often on HN [1].

[1] https://news.ycombinator.com/from?site=matrix.org

[postepowanieadm]

You could send a message from google chat to a fecebook user.

[seba_dos1]

Facebook never federated, so no, you couldn't. You could use an XMPP client to chat on Facebook though.