> Servers: $2.9 million dollars per year.
> Registration Fees: $6 million dollars per year.
> Total Bandwidth: $2.8 million dollars per year.
> Additional Services: $700,000 dollars per year.
Signal pays more for delivering verification SMS during sign-up, than for all other infrastructure (except traffic) combined. Wow, that sounds excessive.
It's also not a great idea to make sign-ups for an instant messaging service contingent on having an account with another, competing service.