“iPhone-only social networking” has been very successful (amongst my US-based peer group, at least), once you include iMessage - that’s the point. I don’t know much about apple invites, but if it integrates well into iMessaging then this is a very strong play.
Just the way I wrote the reply. It's unnecessary. Yes, you send a text and it's iMessage or not iMessage. Doesn't matter. There are some nuances if you're on your Mac with your phone off/on an international SIM (which I admit to not totally understanding).
