The Do Not Call registry, a system put in place after millions of people made it clear that they despise telemarketing, has been one of the relatively few success in the "war against advertising". While advertising in and of itself is not bad, nobody wants to get calls on their cell phones. One reason the DNC registry has worked was the looming threat of fairly severe penalties if a company did not comply with the list.
A few companies haven't, and not the fly-by-night operations you'd expect to operate outside the law. Big names like ADT, Ameriquest and others have recently earned the ire of the FTC for failing to comply and as a result the FTC divied out $7.7 million in fines. For such a young system, it's actually surprising the FTC has moved this fast. Obviously being targeted by telemarketers on your cell is a lot more intrusive than most forms of advertisement so it gets people heated up quite quickly.
The FTC maintains a complaint form for people to report companies abusing the list.