I recently signed up with Credit Karma and a printable coupon site and my phone has had one solicitor after another, mostly those education ones that just hang up. Annoying because I can block one number and a different one calls saying the same thing. When I called it back it had an option for the "do not call" registry.
The message I received was that it was a furthering your education crap. Considering it came to my partners phone it had better not be a match making service. I just switched to the iphone and noticed you can block callers.