[sterlind]

I'm not sure about Google, but at MS we absolutely use our own cloud heavily. sometimes there's big legacy stuff, but nowadays most of that has gone onto Azure under the hood. I've heard Amazon is much the same way.

the only exception I can really think of is infrastructure that you need to recover from disasters, which isn't on Azure for obvious bootstrapping reasons.

[paxys]

Until I was at Microsoft a few years ago there was always a struggle to get internal teams to use Azure. There were constant talks to get O365 and Bing (so, the bulk of internet-facing servers) on Azure, but nothing never materialized. I have heard Google is a lot worse in this regard.