Yes, I've read their privacy policy. Where does it tell you how long they retain your data? Or whether your data is disassociated from your identity? This is important when you consider how personal your online activity can be. Who sees your data at Google? All the privacy policy states is "We restrict access to personal information to Google employees, contractors and agents who need to know that information"

While Google automates scanning of your emails in GMail, they don't tell you if that is the case with the other personal and private data they hold about you. Yet your activity across the web is arguably just as personal and private as your emails. That is why anonymising or disassociating your data from your identity is a legitimate concern, as are questions about whether your online activity is anonymous when viewed internally by Google.

Let me put it another way, if I ask you to give me your name, gender, date-of-birth and mobile phone number (as Google does), then proceed to record the searches you undertake as well as sites you visit and videos you watch, would you not expect me to tell you how long I keep that information for? Or whether it's anonymised before internal staff pore through it? Or whether it's aggregated in a way that isn't personally identifiable?