Alma Whitten, privacy director for product and engineering, explains:
According to The Washington Post, those who use Google's services will not be able to opt out of the latest changes, which will become effective March 1. So has Google forgotten how much flack Facebook fought off every time it made changes without giving users an option? Not exactly. Whitten assured users, "We try hard to be transparent about the information we collect, and to give you meaningful choices about how it is used."
If that's not enough, users always have the option of discontinuing their Google accounts, or any one of the Google services accessed by those accounts.