[hexa22]

They did a terrible job of it. They broke all existing comment trees and pushed google+ really hard and automated posting. I seem to remember that commenting on YouTube would then make a post on google+ with your real name and likely notified your contacts about it.

[toyg]

They clearly didn't want to be left stuck with maintaining multiple authentication systems (legacy ones and G+), so they thought they'd eat shit for a while but results would be worth it. But they executed so forcefully, that the backlash eventually forced them to backtrack on the most visible properties. This said, now every product they create or acquire gets wired to a single authentication system, so I guess they did make some progress, even though it's a "Google account" rather than a "G+ account".