Since a lot of you are asking - this doesn't store numbers, collect data, or track anything other than hits via Google Analytics and API hits on Twilio.
No marketing scam, no selling of address books - just a little hack to make people smile.
I really, really really, really really really hate things that collect data and use it for marketing purposes or spam. I added a disclaimer to the bottom of the page (thanks @seszett for that idea) with words to that effect too.