Users only need to remember their own phone number - you send a temporary activation code via SMS to register - as painless a signup as you can get Meanwhile i

Users only need to remember their own phone number - you send a temporary activation code via SMS to register - as painless a signup as you can get Meanwhile it sets a higher bar than an email address for fakes signups; as a developer you have a higher degree of confidence that most of your signups correspond to a real person, which can help reduce abuse etc.