The Do Not Call List is only for telemarketers making sales calls. There are certain types of calls still allowed to be made to people on the Registry. The following calls are allowed as long as they do not contain a sales pitch:
Surveys
Political calls
Charitable calls
Purely informational calls
Debt collection calls
You can also receive calls from companies that you have recently done business with, and these calls can include a sales pitch. These companies can only call you with your permission and you can ask them to stop calling you.