Google has some elements of greatness. It is an organization that thinks long term, makes rational decisions backed by data, is bold enough to go against the tide at times, and is actively trying to avoid doing evil. Google has its limits however and the recognition of those limits by the users (us) and Google (them) will be very important in the years to come.
Even though many of Google's services are offered free of charge, they are still services and they are in fact governed by terms of service which are actual written agreements.
In the negotiation of written agreements the issue of trust is central. Often the language in a written agreement is overly advantageous to one side. Anyone who has read a loan agreement knows what I am talking about. When making sure that a loan agreement accurately reflects the terms of the deal, the borrower must question both the language and its intent. When doing just that we are often met with the response -- "We (the bank) would never exercise those rights, don't you trust us?". The best answer is: "I trust YOU, but I need to protect myself in the event this agreement comes under the control of someone other than YOU".
When we apply this thinking to our relationship with Google or Facebook or any other service provider, things get a little frightening. I do agree that Google is a great company, and that its goal to do no evil is sincere. What happens however when there is a leadership change at the company? What happens when the current leaders retire, or the company falters and they get pushed aside? The agreement Google has with its users would quickly be in the hands of different people and those people may have either a different definition of evil, or a general predilection to pursue it.
What if a new banker showed up at your house one day and said -- under the terms of our agreement I am taking all of your stuff?