Very late to this party, but...
I'm used to my dentist's office manager calling me every six months to remind me about my cleaning appointment. This last time, the call was automated and I instantly thought "hey, Appointment Reminder."
No, it turns out it was SmileReminder that the dentist uses. When I went in for the appointment I spoke to the office manager and the light in her eyes was obvious: "Now I don't have to spend hours calling everyone to remind them. I love it" No idea how much they pay for the service, but it's obviously worth it to them.