Craig Ferguson was an alcoholic through the 1980s, and only got into rehab on the good word of one of his comedian friends. Due to his first-hand experience with addiction, he won't make jokes about people showing signs of substance abuse.
Fan Community Nicknames: Craig himself uses "hobos" for his studio audience, and "robot skeleton army" for his Twitter followers.
Keep Circulating the Tapes: It's not out on DVD, since David Letterman apparently believes repeats hurt the value of the first-run episodes of his shows, but most (if not all) episodes since 2009 are floating around YouTube right now. Neither Craig or CBS really seem to mind, mainly since A) it gets Craig more international exposure, B) there's no annoying unskippable ads every few minutes, and C) there's no commercials period.
The Craig fans were hit hard in early 2010 when Malinky2Stoatir, probably the most well-known uploader of Late Late Show episodes (and a gigantic Craig fan herself, not to mention a very similar sense of humor) — whose uploads were watched by tens of thousands of subscribers around the world — had her account pulled down by YouTube. She quickly returned with a new account called "TVsCraigFerguson" and continued uploading new episodes (along with classics from the old channel) until it was hacked, at which point she moved to TVsCraigFerguson2.
While the show itself hasn't directly mentioned Malinky and her work, it's pretty obvious that they know about her: for one, she has a Twitter account, and one of her 5,000+ followers is none other than Craig himself.
One of Us: Craig has fully accepted his status as a Whovian, much to the rejoicing of Whovians across the world. He has also been on the Nerdist podcast, and The Late Late Show is generally considered the late-night show for nerds.
He also mentions his Whovian status in the Stan Lee interview (see the Funny Moments tab).
Craig: I'm not even a proper fanboy, because the people who go to Comic-Con — they all know about stuff. I'm like "Huh, Doctor Who's cool!" and they're like "Oh, which Doctor, loser?" and I'm like "I don't know!" You see what I'm saying?
An email segment in November 2007 included a letter asking for baby names. Craig, admitting it as being "the only name I know", suggested...Susan.
The Big Bang Theory crossover sketch had Craig state facts about Doctor Who after he fails, trying to impress the group...although he mistakenly refers to the main character as "Doctor Who", which would hit the Fandom Berserk Button of many Who fan forums.
He even gets in an argument with Chris Hardwick about whether the Doctor is a superhero.
Craig: He wasn't sent to Earth, he came of his own accord. Superman was sent to Earth, Doctor Who wasn't sent to Earth. He came of his own accord. I think there's a difference.
Geoff Peterson's mouth and arms have stopped working more than once. They just kept on going, with Craig claiming that Geoff was communicating telepathically. In another memorable incident, Geoff's right hand popped out in the middle of a show.