The Signal Foundation received a zero-interest loan of $100,000,000 by WhatsApp founder Brian Acton which doesn't need to be paid back until the year 2068 or something.
And according to Telegram's Pavel Durov, "A project of our size needs at least a few hundred million dollars per year to keep going." [0]. So future funding sources will be needed if Signal grows to be a big player. It's fine saying they're owned by a non-profit, but even non-profits have bills to pay.
I don't think a project of that size needs that much money.
Exhibit A: The Signal Foundation's tax reports[0]
Exhibit B: The fact that WhatsApp had a very small team and rather low costs, at least prior to its acquisition by Facebook. (I can't find any numbers right now.)
According to this Wired article [0] from last year, the number of Signal users aren't public, but they've had "more than 10 million downloads on Android" and another 40% on iOS. Lets say 20 million downloads in total. Of course there's more now, but we don't know what kind of costs they have now, and I couldn't be bothered looking for more recent figures.
Telegram has close to 500 million active users each month. So of course Signal is not using as much money. The same Wired article mentions that Signal recently had gone from 3 to 20 full time employees, that adds a lot of cost as well.
My point is that I don't think Telegram have spent lavishly or focused on big profits, so it's unreasonable to assume that Signal will be able to do what Telegram does for much less money, so they will also need a new monetization eventually.
