Share your insights or perspective on the financial matter presented in the input.

How profitable is selling your customer base? 
but what about non-identifying information like emails or even telephone numbers? Are you allowed to do this? Most countries have privacy laws that would explicitly forbid companies from selling data not just to other companies, but even to other divisions within the company without explicit approval from customer.  There are adequate regulatory controls that would stop companies from indulging in such practises. However tons of smaller / un-registered companies or companies operating from certain countries are definitely a source for such practises.