Which marketing channel is used to collect email addresses through a point of sale system?

The marketing channel used to collect email addresses through a point of sale system is in-store. This method typically involves interacting with customers at the physical location of a business during the transaction process. When customers make a purchase, they often have the option to provide their email addresses either for receipts, loyalty programs, or for promotional communications. This direct interaction allows businesses to gather valuable contact information from customers in real-time, creating opportunities for future marketing efforts such as targeted email campaigns.

While online channels involve collecting email addresses through web forms, social media platforms focus more on brand engagement and awareness rather than direct email collection. Digital advertising can promote products or services but does not typically serve as a mechanism for directly collecting email addresses at the point of sale. Thus, the in-store setting is specifically designed for this personal interaction and data collection approach, making it the most appropriate answer.