In the past, Google had separate privacy policies for each service. Now, by applying a single, uniform policy across services, and merging all it knows about you into one database, the company says it can personalize your Google experiences to make them more relevant to your needs.
Critics are unhappy because it's not possible for anyone to opt out. If you sign in, you're identified across all the Google services, and your data will be collected, whether you like it or not. Gmail may be convenient, but it will be less private because Google will use what it finds in your messages plus what it sees you watching on YouTube or writing on Blogger to present you with targeted ads.
You may, as Google points out, get more precise information when you search, because Google knows so much about you. And there are likely to be other benefits that will emerge as people learn to use the new system. Still, the privacy aspect is quite controversial.
