[palata]

As much as I hate cryptocurrencies and the MobileCoin effort (that should never have been part of Signal IMO), I think that "playing with MobileCoin" was low-risk as a side project (that never took off as far as I know?).

However, moving from phone numbers to username seems very tricky to me.

- They have built their system around the idea that they can use the address book that already exists in users phones and not learn about it. It works (at least in theory), it's just that some people don't trust them for that. Or some people have a threat model that is incompatible with that, I suppose. Changing their whole system for a very small minority of very vocal users is a risk. Also if going for usernames makes them collect more metadata, then other users will complain (or maybe even the same that currently complain about the phone numbers).

- Most people use WhatsApp, of which Signal is an improvement in terms of privacy. Those people don't give a damn about sharing the phone number, so the reason why they don't move to Signal is surely not this (because Signal certainly doesn't do worse with the phone number). So changing that would be a risk.

Moving to usernames is a cost, and a risk. All for a few very vocal users who probably have a threat model that requires it. I would understand if they never moved to username, and I would be fine with it.