I genuinely do not understand people who have deep fried opinions about Signal needing a goddamn phone number in 2025.

Many privacy nerds were outraged when you needed to give out a phone number to other people in order to talk with them. I was one of those nerds. They fixed that with the usernames rollout.

As a mobile phone app, Signal uses your phone number to bootstrap your enrollment into the protocol. This is literally the path of least resistance as an SMS replacement app, for most users.

If you want to know whether Signal can obtain enough metadata to target users that have enrolled, the answer is complicated.

The way profiles are encrypted, and how sealed sender works, makes any targeting seem infeasible. (Your profile key rotates, at mininum, when you block someone.)

Signal currently does not have IP addresses, etc. stored. If this changes in the future, it will not be retroactive. If you're worried about that, Molly boasts Tor support. Maybe that's fine. I haven't audited Molly, and won't.