When the petitioner creates the account and identifies some supporters, they can identify up to 10 individuals. We're not that aware of how they interact with those individuals beforehand, but clearly, individuals are identified. In some cases people just identify five, and maybe one of them is not exactly as good a Facebook friend as you thought they were and will not be support the petition. That's where some difficulties arise.
On May 8th, 2018. See this statement in context.