On: Twitter Digits

[jqueryin]

Counter-point: It's hard to track SMS after a few carrier hops, especially in third world countries. There is no guarantee on delivery to recipient unlike email.

[jakozaur → jqueryin]

Exactly, some carries drop sms on different occasions and you never know the status.

Also I would argue if you target ppl who don't have email you shouldn't require any authenticated accounts.