Continuity mistake: When Blair asks Mitch "why aren't you answering me?" he says he got a weird message from Laura Barns. Blair replies "that's not funny" and Mitch replies "I'm serious." Then Blair gets a message from Laura, and when she switches back to Mitch's conversation, the last two entries, "that's not funny" and "I'm serious" have disappeared. (00:10:50 - 00:12:30)
Continuity mistake: When Laura Barns posts the photo of Val Rommel on Val's Facebook page with the curling iron, Facebook says the post is submitted in November. It should have been in March, the anniversary of Laura Barns' death.
Answer: Blair's friends were responsible for some of the online bullying, but she said everyone is doing it, so they did. That's the only thing I can think of anyway.