Customer Relations Management (CRM) describes the strategy that a company uses to handle user interactions. 

The CRM records and manages all user details, conversation history with support persons, and transactions. These records make it possible to get reports on shopping history and make predictions.  They also help talor specific coupons based on a users buying history.  Knowing the users full details and conversation history make it much easier for support staff or sales people to better help the user with any issues.  The CRM can also be used to make frendly 'Thank you' emails for regular customers or a 'Happy Birthday' letter.