What business model is Signal based on?
When ideals are involved (strong encryption, privacy, ad-free), being run as a lean, open-source project is worth much more than being owned by a megacorp like Facebook.
No, I did not :-P
You donate bitcoins to a pool. Everyone can commit to their repository. Every merged pull request gets 2% of the pool. Currently you get 26.98 USD per merged pull request.