The Mortgage Acts and Practices - Advertising Rules (MAP Rules) are designed to prohibit misrepresentations in a commercial communication regarding mortgage products. Under the MAP Rules, any person engaging in commercial communications regarding mortgage products must retain records records of all "materially different" communication.
Under the MAP Rules, there are essentially no limitations on what qualifies as a "communication." Given the openness of the "communication" definition, the MAP Rules cover all communications including those via email, text messages, and social media.
Link to MAP Rule FAQ: https://www.parealtor.org/wp-content/uploads/2016/06/MAP_Rule_FAQ.pdf