I feel like this is fine as long as it's opt-in. I cannot imagine having to go back and fourth about calendar slots every time I have to schedule a meeting, and this feature saves so much time.

> Or see stats about the changelists submitted, bugs resolved, etc. of each person?

I'm a bit ambivalent about these metrics. At least they are somewhat related to work results, rather than "how busy are you" metrics like those rolled back by MS. It's also just a visualization of data which is already publicly available in the git history.

> Or see their dot when they are viewing a document?

This one I think is a bit different. In a world with remote collaborative editing, I think this gives you more visibility about who might be looking over your shoulder while you are working rather than being a form of surveillance.