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Comment by tptacek

2 years ago

I feel like Signal has been up front for many years about why they use phone numbers, and I get incessant spam on other phone number platforms (most especially: phones) so I'm not sure that holds water.

They seem to actually confirm it themselves, which I didn't know.

> We use third-party services to send a registration code via SMS or voice call in order to verify that the person in possession of a given phone number actually intended to sign up for a Signal account. This is a critical step in helping to prevent spam accounts from signing up for the service and rendering it completely unusable—a non-trivial problem for any popular messaging app.

From their blogpost

  • I'm sure they absolutely do use it as a spam signal. You use what you've got. But that's not why they use phone number identifiers, which is a design decision they and others have written ad nauseam about.