The model I'm thinking of is freemium -- allow free usage over SMS for most consumers, then charge for those who sign up for business-level features.

What's got me thinking is that, unlike a classic website/app model, using SMS means I could be burning quite a bit of cash. Heck, it meas some random competitor could just start making me spend money for nothing (From what I understand, guys like Twilio will charge you for incoming texts even if you don't want them) It's like opening up your wallet and asking people to take money out of it. A very different model from the kind of control over costs I'm used to having.

But perhaps I am borrowing trouble.