Privacy and anonymity are distinct concepts. Signals provides very high privacy and low anonymity - which is totally acceptable for many people's threat model.

Other apps may provide higher anonymity, but none provide privacy guarantees higher than (or even close to) Signal.

Privacy and anonymity are distinct, but strongly correlated. Without anonymity, there will always be enough metadata to hang you with. Using Signal as a surveillance-evasion-tool will get you into trouble in a lot of the more unsavoury corners of this planet.

So, being "best" at privacy is meaningless unless you are in the very lucky position that your local jurisdiction fits Signal's threat model. There aren't many in the west even...

Meaningless? I value private communication with my friends and family. I don't exactly need anonymity there. In fact I want the opposite. In the absence of phone numbers I would be adding very explicit metadata on my device to distinguish between my friends.

Signal has taken measures to limit its ability to know who I'm sending and receiving messages from. Though it's still possible by mapping my IP address to me. So yes there is still a centralized metadata problem, but I'm not letting perfect stand in the way of better.

>Without anonymity, there will always be enough metadata to hang you with.

Not in most cases, for most people, most of the time. Everyone knows you communicate with your family, friends and business associates. Very few people communicate out of those groups and even if they do they rarely have to worry about anyone finding out about it.

Umm... in fact "most people" communicate outside of those groups, as that's how dating works, and it is a big reason why Snapchat dominates "private communication": people don't want to give their "real phone number" to someone until they trust them. Signal needs to realize its big competition is not WhatsApp, but is Snapchat (particularly given that WhatsApp is pretty damned secure, and so should be seen as an ally versus all of the actually-insecure messaging apps of the world).

Idk how giving someone your Snapchat/Instagram is less risky than giving them your number. You can block people from calling/texting you. In fact iOS recently came out with a feature that blocks all incoming calls/texts from unknown numbers. So even if you give somebody your number and they are evil enough to sign you up for a robocall list it would still be fine

I feel like that’s a handwavey academic answer. In real life situations you always need both privacy and anonymity. Do you think a gay rights activist in the Middle East wants all of their contacts to know their phone number and therefore their personal identity?

can anyone commment on the design consideration that the telephone requirement addresses?

This is designed to make Signal more popular while solving some fake account issues:

- Using phone numbers means that Signal can constantly check against your contacts to let you know if any of your contacts are now using Signal. As such, using phone numbers encourages use of Signal.

- The usage of phone numbers instead of email or usernames also helps combat temporary/fake account creation abuse, as phone numbers are KYC if you ban VoIP numbers

That said, in the end it is a compromise on privacy and anonymity to increase the popularity and stability of the app.