Why does Signal, an app that claims to value privacy, require you to have a phone number? I’m going to share the two reasons they’ve talked about and my thoughts on them. I also want to share what they’ve added, as of February 2024, to help mitigate the downsides of requiring a phone number requirement.
Reason 1: Limit spammer abuse
Signal is free to install and use. Which means spammers will inevitably try to register as many accounts as they can as another way to send more spam. I watched an interview with a bigwig from Facebook and they discussed how many millions of spam accounts they have to delete daily. Signal does not have the resources to do that. Instead, they require a phone number. This makes creating multiple spam accounts much harder, as phone numbers are a scarce and difficult to obtain resource.
Reason 2: Improve adoption
This may sound self serving, and of course it is. But unlike many apps, Signal is useless for any single individual. It’s for people to talk to each other. In order for Signal to deliver on it’s goal of providing a safe and private means of communication, it needs wide adoption. It needs to be easy to find and connect with your friends on Signal. A phone number is already a familiar means of doing that.
Responding to criticism
So, how has Signal responded to the criticism about their phone number requirement? They agree! They don’t want to require a phone number, but until a superior alternative is available, they are keeping it. But they are also making careful changes to help mitigate the downsides of the requirement.
Usernames and phone number privacy
Specifically, in February 2024, Signal added usernames. A new way of connecting with others on Signal. This means even though Signal still requires a phone number, you never have to share your phone number with anyone else This is a huge step forward. It has allowed us to use Signal as a means of communicating with our members without giving our phone number to everyone. It also means you can turn off phone number discovery entirely, and guarantee that no strangers can ever connect with you.
No perfect solutions
Despite the criticism, and my own initial hesitation, I have come to appreciate Signal’s decision about phone number. I believe it’s one of the key reasons they have managed to stick around, and continue to grow. There’s no point in building an awesome communications app if nobody uses it. There are no perfect solutions. But so far at least, I agree with Signal’s approach to the thoroughly tricky problem they are trying to solve of providing a safe and private communications app.