We now know that not only did Google unethically collect this information, but they did not delete the information correctly. It makes you wonder what information is being collected that is not currently being used for anything. This goes even further when you look at the amount of personal information collected by mobile devices like smartphones. Steve Jobs had an interesting take on the problem.
I would take this a step further and say that sharing of information and total transparency is the key. There are significant advantages to be gained to giving customers control of the information that you hold about them. Giving them control of their information makes them accountable for the quality of it. Wouldn't it be great if every 6 months we sent our customers an email for them to check their contact data and revise their privacy agreement and preferred contact methods? Carrying out the process could entitle them to discounts or extra services.
More importantly, when everyone works together, trust is built. Customers get back the control and businesses get a feedback loop to keep details updated and quality high.