51 Million

That's how many numbers are in the national Do Not Call registry already, which the 10th Circuit has given the go-ahead for enforcement while its constitutionality is further scrutinized. More at How Appealing; the Los Angeles Times.

Some interesting particulars: As the 10th Circuit's order (PDF) points out (p. 17), since 1995 the Telemarketing Sales Rule has "prohibited telemarketers from making sales calls to persons who had previously stated their desire not to receive such calls from that solicitor." 60 Fed. Reg. 43842, 43854-55. This rule applies to a business "organized to carry on business for its own profit or that of its members." Id. at 43843 n.14. Moreover, as the order also observes, under the 2003 legislation authorizing the national Do Not Call registry "consumers are also given some mechanism to block non-commercial solicitations by means of company-specific objections to solicitations by charitable organizations." (Order, p. 22; emphasis added)

It should go without saying, but don't let telemarketers snow you. Even if they are exempt from compliance with the national Do Not Call registry, and/or the 1991 Telephone Consumer Protection Act (see Private Citizen's description of its exceptions, or, as they put it, "loopholes that telemarketers can drive a boiler-room through"), they still may have to stop calling if you ask—nicely or not.