I've been quite wary about this area - I never like anybody's brand of toolbar, including Google's. I'm extremely aware of whether I'm logged into a Google account or not - I don't want them looking at all my search habits.
I do appreciate the Webmaster Tools, but just to the point that the tools authenticate domain ownership and report back to me what Google already knows. I know of several big corporates who are extremely concerned about business espionage, but still use Google Analytics and even conversion tracking. Now that's some cognitive dissonance in my book.