Visitors can sign up for SMS notifications. (Please use the SMS marketing service of your choice in conjunction with your mobile pages).
Create a page with a Button with the action of “SMS Shortcode” and a description (for instance: “Sign up for text message updates. Send us a message with the word ‘pizza’.” )
The short code is just a short number – e.g. 345345 from which and to which the text messages are sent.
When the visitor opens this page, they click on the button – and that opens the SMS on their phone (so that they can send a message with the word pizza to that short code).