My browser of preference is Chrome, so this extension caught my eye. I'm not sure what I could do with the information, but it seems interesting to track it even if they're using alternate algorithms and it's PIT (point in time) of install, not retroactive. So there's no way to really track what you've already told them. And there's code! For some reason the idea that there's something particularly useful that could be done with the fact I can get to the source code is bouncing around in my head. And let's not say that the useful idea is installing a stealth version on corporate computers to track overall corporate culture tendencies (you can obviously track time on Facebook via the corporate logs). I can see a good and a bad path having that data - start to push your culture toward a new culture (top down "I want this") or recognize the corporate culture you attract and double down. Then again - you'd have to have a separate (or modified) add-in to track other social media platforms.
I work with a lot of lawyers and they're big on capturing billable data. I wonder at what point someone decides "we should capture everything" to examine potential for billable work through other services as well as innate biases in lawfirm partners by examining total web activity. They often want to capture email and text data (although text data is notoriously insecure), so web activity isn't such a big hop.