200M users/yr does not sound unrealistic to me given the network effects of Signal. I'm certainly not suggesting that's the actual rate - but I'd be willing to believe it's within an order of magnitude.
> Here's an article from last year mentioning 50M+ downloads in 10 days.
That was a period in which WhatsApp had just announced their new ToS, indicating that the data about their users was to be merged with Facebook's. Consequently, many users became aware of the enormous privacy issues with all Facebook/Meta products, and abandoned WhatsApp for other services, mostly Signal and Telegram.
I doubt that this period can be used to interpolate the Signal growth for the rest of the year, although the network effect has probably resulted in a much higher growth rate than before the WhatsApp exodus.
Edit: a Tweet from Elon Musk ("use Signal") most probably contributed a lot to that raise in awareness, and the one-time surge of increased growth for Signal.
Here's an article from last year mentioning 50M+ downloads in 10 days. https://webcache.googleusercontent.com/search?q=cache:hsVnnQ...