The owner of the company that cut the film's trailer, Robert "Smitty" Smith at In Sync Advertising, was an actual intern at WXLT-TV who knew and was friends with Christine Chubbuck. He sought out the job when he found out about the film and saw it at Sundance; incidentally, the creators had tried to seek him out for interviews during the research phases, but were unable to locate him due to the ubiquity of his name.
Both lead actor (Michael Hall) and actress (Rebecca Hall) share the same last name (unrelated) as well as both having spouses named Morgan, which is incidentally is also the last name of the character Michael played on Dexter.
The trivia items below may give away important plot points.
A video copy of Christine's suicide is confirmed to exist today, in the hands of station owner Robert Nelson's widow Mollie, who has no plans to make it publicly available. The filmmakers never considered seeking it out.
Christine's suicide took up 3 days of shooting. Initially much more footage of her suicide and its aftermath were filmed, but were edited out to avoid sensationalizing the violence of her act; for this reason, the filmmakers also avoided shooting her suicide in close-up.