A Falkor user can create an account in two ways:
By signing up to a public Falkor app.
When a user signs up to your app, they are signing up to the Falkor platform and, when doing so, they create a Falkor account. This prevents a user who is using multiple Falkor apps from needing to create more than one account.
Another way to think about this is the following:
You create an Apple ID with Apple.
You use this account to download and use apps.
Your account is with Apple, not the app.
Falkor is similar in that:
You create an account with Falkor.
You use this account to sign in to public Falkor apps and/or apps you have been invited to.
Your account is with Falkor, not the app.
When an app is public, groups can still be used to handle content access, but anyone can sign up by creating an account or by using their existing Falkor account.