Google is getting in the health records business. What happens when a single company has full access to your emails, your videos, your family pictures and your health records?
Abuses are possible, but I predict that not much will happen. The American NSA is recording and mining a large fraction of all Internet communications. The same is happening in China.
Privacy is an illusion. Even if governments and businesses did not spy on us already, cryptography and technology does not protect you against social engineering. Even if all your data was safely guarded by the best possible technology, a secretary with a USB key can open up all of your data to mobsters, political opponents or your wife.
How can we fight back? Sadly, I believe we will need to change our expectations. Lots of people will know about your secrets, get used to it. If you have cancer, people will learn about it. If you cheated on your wife, people will know. We are moving toward Brin’s transparent society whether we like it or not.
As for Google… unlike the Chinese government and the NSA, Google has given me powerful tools to offset my loss of privacy.