"Like many start-ups in this area, it is seeking to grow quickly and discover a sustainable business model later." The original value promise: end-to-end encry

"Like many start-ups in this area, it is seeking to grow quickly and discover a sustainable business model later." The original value promise: end-to-end encryption, free app, protection from ads, won't sell your data, won't store your data. What business model do they expect to discover later that won't break the promise?