In an independent.co.uk article, Google chief Eric Schmidt expresses concerns over the amount of personal data people publish online without considering the possible privacy implications.
Personal data will increasingly become a monetizing commodity among the social network and search engine services, while privacy and protection from data exploitation will diminish until its true value is appreciated.
While social network services bring functionality that allow people to connect in new and unexpected ways, email is inherently private and personal to the sender and recipient, as long as that privacy is enforced with a balanced policy.