The next useful piece of information I receive from one of these sites will be the first. Here's the deal guys; they'll hang up unless you play along. If you DO, you can actually find out who they are and do something about it. I've yet to see a single person figure this out. Only reason I come to these sites is a futile effort to see if someone actually had the brains to suss them out, in cases where I missed the call and am researching the number. Never mind.
The DNC is strictly for residential private phone numbers. Political, religious, and commercial sales calls to commercial business entities are exempted. Best thing is: Never answer calls that have "Local", "Unknown Caller", a duplication of the original phone number (1-800....), or a local number that appears to be from your area code but doesn't have a valid identification, or worse yet those damned cloaked numbers that pose as a local call until you find a foreigner on the other end.
Whatever you do, just don't answer. When you do they record is as a valid number and will call until the cows come home...hard to do when you never owned cattle. I switched to Vonage and while they do not have the features we desire, they at have the caller ID down. Phone rings twice, and then they get the message that we do not accept solicitation calls. The number has decreased dramatically.
Not what I would prefer in a phone messaging system, however, once pre-screened they then get to our normal voice messaging system. Yes, it is a bad thing when the phone doesn't ring, the other thing worse is the phone ringing off the hook and they are solicitors. I opt for the former than the latter.