Not the same scale but Signal has a rather new approach for a messaging client. Completely free and funded by user donations - at least that’s the direction they’re trying to head as their initial seed funding starts running low. I’ve doubled my donations for Signal because I’d like to help prove that its a working model and I encourage everyone who uses it to donate, even if it’s just once. I’d love to see Firefox head in that direction where funding goes directly to the browser’s development. If I donate to Firefox today it might go to one of their dozen or so other pet projects that are unrelated to the browser. I think their side projects are great and glad they were able to do them while they had the cash, but funding is clearly drying up and they need a whole restructure to keep the browser alive.