“ The smart marketer will approach the question of value as if the answer is zero — there is no intrinsic value to a Facebook fan. This might sound sacrilegious to social media marketers, but think of it this way: What’s the value of an email subscriber if the company never uses the database for anything? And what’s the value of the same email subscriber if the company has a smart, user-focused strategy for email? It is what companies do with fans that creates value, not merely that a brand has fans.”
Source: blogs.forrester.com