I've just been working my way through various lists. It frustrates me greatly that the public is expected to do go through this effort to "opt out" rather than the sleazy stalker companies being required to get opt in.
There are 100+ agencies you need to file with, and you need to follow up several times as your data can be re-syndicated between them during grace periods. It is -lot- of work which is why efficient services who've optimized this are likely worth the money.