There seems to literally be no way to turn off that freakin annoying red dot in gmail; even in the notifications settings of Google+, it only lets you adjust sms/email notifications. I'd previously had to make my own userstyles to edit the css to hide the notifications, but they kept reappearing every few days. Hopefully this Chrome Extension will banish them once and for all.
Currently it only works in Gmail (where I spend most of my time), not google docs, but it seems to be being actively maintained, so hopefully they'll roll it out across more properties.
Hustle X