I know we've said it at committee before, but the Americans are the last remnants of the opt-out regime; everybody else in the world has gone opt-in. Basically it's a “you can spam” act. It permits spamming, ultimately.
The marketing lobby in the United States was successful. That was not their original intent, but they were very successful in lobbying our American counterparts to put that in the legislation. Over the next few years, I'm sure we'll see the American folks having a look at moving to an opt-in regime.
A couple of countries have already started with an opt-out regime and transitioned to an opt-in regime on a similar model, like Japan.