They could have been Slack if they didn't transmogrify it into a social media platform (Google+) and then throw out the baby with the bathwater when it failed.
I’m talking about something much more fundamental, the entire company would pretty much implode within 24 hours (or at most a week) if they couldnt verify who is who.
You're really giving credit in the wrong areas. Google is impressive for its ability to exist beyond the point of dysfunction. It's simply not the case that any Googler would need to verify the identity of any other any more than it is necessary for every server to verify the identity of every other. They only need to verify the identify of the tiny subset they are communicating with at any given time. This doesn't mean everyone has access to a coherent org chart, or that one even exists.
> Ask their managers? But then how do their managers verify?
It's a hierarchical org chart. If you're really not sure ask Sundar.
It's likely any Googler can verify the identity of any other by looking up their username but it's unlikely that the same tool would do something like tell you how the YouTube recommendation algorithm works or who would know that.
They will know the names of frequent collaborators and something about the scope of relevant work but it's not like everyone at Google needs intimate knowledge of every workstream. At that scale it's unlikely anyone has the full picture.
We agree an org chart of some kind probably exists. We disagree on the capabilities. For example I am not confident that it has a concept of a team and if it does that a team would map to a product or feature.
They could have been Slack if they didn't transmogrify it into a social media platform (Google+) and then throw out the baby with the bathwater when it failed.