Comment by thaumasiotes

> In response to increased verification traffic from apps like Signal, and decreased SMS revenue from their own customers, these service providers have significantly raised their SMS rates in many locations, assuming (correctly) that tech companies will have to pay anyway.

There's nothing that requires tech companies to use SMS for registration or for 2FA. The normal way to do it is by email, which continues to be free. For Signal, there is no need to do 2FA registration at all.

Signal is ideologically committed to publicizing your phone number, and apparently they'd rather pay $6 million to hold to their commitment than just... not do that.