How has the implementation of the National Do Not Call Registry changed telephone marketing?

What will be an ideal response?

The National Do Not Call Registry was created by legislation, passed in 2003; it bans most business telemarketing calls to registered phone numbers. However, people can still receive calls from nonprofit groups, politicians, and companies with which they have recently done business. Millions of customers have joined the do-not-call list, and businesses that break the laws can be fined heavily. The use of unsolicited outbound telemarketing has greatly decreased due to the law, but inbound consumer telemarketing and outbound business-to-business telemarketing remain strong and growing. Many telemarketers are shifting their call-center activity from making unsolicited cold calls on often resentful customers to managing existing customer relationships. They are developing "opt-in" calling systems, in which they provide useful information and offers to customers who have invited the company to contact them by phone or e-mail.