Demand Overload: The site used to slow to a halt whenever a new comic was posted, though this was mostly because of all the people hitting the forums.
Exact Words: Rich Burlew is known to sometimes indulge in this in the forums as not to spoil some yet unrevealed twist in the story. For example, when pressed about what god Vampire Durkon would worship after his death, Rich pointed out that non-theistic clerics can exist in D&D, and that it was likely for a cleric turned vampire to become one. But he never specifically said that Durkon was such.
Fandom Nod: Many, including Miko (not) becoming a Blackguard or Death Knight.
Originating from his own words — Belkar is the SEXY SHOELESS GOD OF WAR.
Durkon gained the nickname "Durkula" very quickly on the official forums once he got vamped. Got a Fandom Nod in "Naming Names", where it's one of many options rejected by Roy when he tries to crowdsource an In-Series Nickname.
In Memoriam: Veldrina's bodyguard Wrecan is a tribute to a late member of the comic's forum.
Jossed: The author states that if he comes across a fan's prediction that happens to be true, his first instinct is to spite the fan by changing the story arc. As a result, he tries to avoid speculation conversations on the forums.
We get a pre-emptive Jossing from Thor, who announces he has to show Durkon something on the Astral Plane and immediately clarifies that it isn't Xykon's secret fortress... something nobody present even knew existed, but a reference to the only other thing the comic has so far referenced being on that plane.
Official Fan-Submitted Content: The characters Veldrina and Wrecan. In the Kickstarter campaign, one of the prizes for large backers would be to have their character have a walk-on cameo for a single page, though the character fit perfectly for a then-upcoming arc in the story, so Rich opted to keep the character for longer. Wrecan is included on a more somber note. He was a prolific poster before suffering from heart failure. His wife said he would have loved to have been included in the comic, so Rich included him.
Old Shame: The Giant has expressed regret in the annotations of the digital releases of the books in regards to how gender tropes and identity were handled in the earlier runs of the strip. In particular, he regards strip 35 and strip 249 as particularly insensitive and uninformed regarding issues such as female objectification and transgender identities, and strip 20 as he now considers rape jokes to be not funny.
Schedule Slip: Early in the comic's run, the author kept up a fairly regular Monday-Wednesday-Friday schedule. Health issues eventually made this impossible to keep up on a regular basis, and he experimented with other schedules before finally giving up and making the official schedule "Updates at random". By the time this happened he was already one of the biggest names in webcomics and his site received more traffic than Marvel's, so it hasn't hurt his fanbase.
Science Marches On: This strip has a gag that a Brontosaurus being just an Apatosaurus with the head of another dinosaur is no reason for it not to exist in a world with griffons and chimaera. The problem is, this is being reconsidered after a 2015 study that concluded it's a different genus after all (although the original head is still wrong).
Series Hiatus: Starting September 2012, the comic was in an enforced hiatus after Burlew seriously injured his drawing hand in an accident. Updates didn't resume until the end of 2012.
What Could Have Been: The idea of Durkon turning into a vampire came up early to Rich Burlew, when the comic was still a gag strip with no continuity, to make a Pun on "Turn Undead". Then the author decided he wanted a more continuous storyline, and the concept evolved into a lengthy story arc which saw Durkon killed and raised as the High Priest of Hel.
Roy's skin tone was lightened a few shades after the art upgrade. Word of the Giant says it's so he'll appear better when the books are printed. The same thing happened with Zz'dtri.
For a few hundred pages, Elan has been cosplaying as Locke from Final Fantasy VI minus the wig and bandanna. After escaping from prison, he dressed up as Locke (and Thog donned a Moogle suit) to sneak aboard the Blackjack, then gave himself away, got thrown out of the airship, and never changed back. The new costume's a large improvement, though.
As of his resurrection in #665, poor old Roy had been dead for exactly one third of the comic.
The following titles have each been used for two strips: "All in the Family", "The Bright Side", "Breakfast of Champions", "Loose Ends", "A Moment of Truth", "Not to Scale", "Resource Management", "Role Reversal", "Running on Empty".