[topdancing]

> Signal uses phone numbers as identifiers because it controls spam.

Signal uses phone number as identifiers because it's the easiest way to find other users. There's no other reason Signal uses phone numbers as a primary ID.

[johnisgood]

I wonder if I ever needed contact discovery, as in, actual contact discovery, such as: you start typing foo, then you get "foobar, "foobaz", and so forth. It definitely complicates things.

[askvictor]

This. Your phone number is your social graph.