I'd like to use SMS in smart campaigns. I've read about Twilio and Informatica. From what I gathered, it's no problems to get the SMS sent. Is there a way that Marketo can see whether SMS has been opened, clicked, and then build a response accordingly via Smart Campaigns? Interested to find out.
You also need to design and opt in/out process by Country. The regulations on SMS are pretty tight and it's easy to get in trouble.