> What does iMessage do to get to all cell phone users? SMS fallback. iMessage is the default SMS app. You send a message to a phone number. That’s it, you’

> What does iMessage do to get to all cell phone users? SMS fallback. iMessage is the default SMS app. You send a message to a phone number. That’s it, you’re already using it. If they have an iPhone too you get extra features. From an onboarding and UX perspective it’s genius/obvious.