The teeth come from the laws, though. If you've submitted an opt-out request in compliance with the law, and your data reappears, the vendor now has a problem with the government. Problems with the government are super bad for your business. They have many more resources than the average individual.
I think that these laws don't have much effect when you require individuals to fill out (literally) 200 forms once a year. But software is great at filling out 200 forms once a year. It's the "missing link" for this kind of law; turning the legislature's intent into a regulation that means something.
I rarely see things that are really exciting to me on HN and that I can immediately start using. For whatever reason, this piqued my interest.