The usual response to any minor factual error in a science-fiction or fantasy related article on the internet.
A nerd swarm is characterised by multiple, repeated corrections to the error along with reactions blown out of all proportion. See also nerd rage
Article headline: "Why Tom Baker, the sixth Doctor, had such curly hair."
Comment: Tom Baker was the FOURTH DOCTOR!
Comment: fourth Doctor Who, dumbass.
Comment: Colin Baker was the sixth Doctor
Comment: He was fourth!
Comment: which curly haired Doctor do you mean, fourth or sixth?
Comment: You stupid bastard! Fourth!!!
Comment: By the blood of Rassilon, I swear that I will murder your entire family for this! Tom Baker was the fourth Doctor!
Comment: You made a mistake. Tom Baker was the Fourth Doctor.
Comment: Fourth Doctor
Comment: Failure! Baker was, like, the fourth.
Comment: Colin or Tom, you piece of s**t?
Comment: Quick! Edit your article! There's a nerd swarm forming! For the love of God, edit it now!!!