These are not automated text messages coming from our servers. And they are not automated invites sent on behalf of users when they sign up for Flock. They are intentional invitations sent directly by a real user.
The flow is: 1) User navigates to the Invite Friends page 2) User sees all her friends in her address book on her iPhone and taps on the ones she wishes to invite (phone numbers are shown below each friend) 3) User taps "Invite" button 4) User is taken to the native SMS UI with the contacts she chose in the To: field, which is editable, along with the link to download Flock, again, which is editable. 5) User must press "Send" on the SMS UI to send text messages to those friends.
You can see screenshots here: https://bu.mp/aPGzVZ
We've tried to make this flow as explicit and intentional as possible while giving existing Flock users a tool to invite their friends to use the app as well.
If there are examples of apps that do this better than we do, we'd love to hear about them so we can improve the flow.
-dave @ theflockapp.com