This is a bit of "with great power, comes great responsibility" situation. It's really easy to piss someone off if you keep texting them. That's why Sonar is all about high touch two-way SMS, and that's largely how Mayvenn uses SMS as well. To use SMS effectively, it's important to let users opt in themselves, so they know to expect SMS and have the option to opt out. Mayvenn places their phone number on their website and asks customers if they want to opt in on the registration form.
