For me it underlines some of the problems with entrusting your personal data to the cloud. That is not to say of course that it is a user’s fault that their data gets shared in such a way – everything in the day to day usage of these tools gives the user a reasonable expectation of privacy.
The trouble is, that this expectation is largely an illusion. When using cloud services, you are entrusting them and you hope that they will exercise the same care when dealing with your data as you would – but unfortunately this is rarely the case.
Whether through carelessness or malicious action information has a tendency to leak. Assumptions made by the design team can be proved poor. So in short, never put anything on the internet that you wouldn’t be happy to see on a billboard.