The Simple Postcard is a text-based service that allows users to send postcards via text message, with the option to include a photo and pay for it via Stripe. The service was created by Jason Strauss, who was motivated by his own experience of wanting to send letters to his long-distance girlfriend in a more tactile way than digital messages. After building the service, Jason learned new tools and technologies, including Python libraries like US Address Parser, which uses NLP to parse address strings. The postcard manufacturing process involves Lob, Twilio, and Stripe APIs. Users can interact with the service through a simple text-based interface, and Jason has received positive feedback from users after it was featured on HackerNews.