Bulk SMS marketing (also known as mass SMS marketing) is mass communications via text message to a database of consenting contacts. In layman's terms, it's sending a lot of texts to a lot of people at once. Unlike pay-per-click (PPC) advertising, sponsored messages, or commercials, it's a channel your customers opt in to receive. Plus, it’s illegal to text or call a cell phone number without prior consent under the Telephone Consumer Protection Act (TCPA).