Devs, that's not how this works. It must be possible to send POW to FB friends even if they haven't joined yet. Otherwise you can just bury this project. Most people are just too inert and know shit about crypto. You won't get enough momentum this way.

Now I know that Facebook doesn't let you post on random people's timelines, so I guess this is how it should work:

• You got the list of my FB friends when I signed up. So you create accounts "in spe" for them. Initial balance is zero. They get their free share only when they actively sign up.
• I can send POW to my FB friends. The POW get credited to their accounts "in spe". I get a share link which I can use to post on my timeline with my FB friend tagged.

That way they know that somebody gave them something called POW, which should make them more curious to sign up than something I posted on my timeline a week (i. e., ages) ago.