Continuity Nod/Web Comics

Examples of Continuity Nods in Web Comics include:

Gunnerkrigg Court:
- In chapter 13, Kat disagrees with Alistair about which is Prodigy's best album, then Alistair gives all his possessions to Kat before he leaves. In chapter 14, Kat is seen wearing one of Ali's T-shirts. Then in chapter 15, she wears a shirt with the XL Recordings (Prodigy's record label) logo.
- In chapter 20, Annie accidentally leaves a giant fingerprint on the moon. Whenever the moon is shown in the background in later chapters, this print is still visible.
When they did a Bleach parody for VG Cats, Leo draws his Rat-Flail (an item he tried to make in a poor attempt at a D&D game by tying a rat to a stick), then turns it into an gigantic living Rat-Morningstar.
The Adventures of Dr. McNinja has its share of these as well. Some even link to Alt Text comments—one memorable one being the Doc's List of Things To Do Before He Died. Another being the peg-faced pirates, and Dan McNinja's 'poison eyes'...
The Order of the Stick has plenty of these, acting as both tiny details and important plot pieces throughout the course of the comic. The most significant of which being an elder dragon who happens to be the mother of a young adult dragon the main characters killed over 400 strips earlier.
- "Wait a minute, I had a 22!"
- In the cast page, Haley is now holding an IOU note after she stole the diamond off the cast page.
- "You're invisible!"
- And then there's the boots that Haley wanted dyed when she bought her new armor. Remember? Those lime green Boots of Speed she found and mentioned to V way back when as what seemed like a one-off gag?
- In strip #685, Buggy Lou mentions that Belkar "was pals with one of [his] suppliers" during Lou's "stint . . . buying slaves over on the Northern Continent." This is a reference to strip #171.

Belkar: The chick, we can sell into slavery. I know a guy who knows a guy.

- And a Lampshade Hanging in strip #683 about a reference from strip #87:

Vaarsuvius: You are a bottomless pit of self-reference, are you not?

- I think Rich just outdid himself in the 703rd strip:

Hobgoblin Mother: You clean that spill up this instant, Hobgoblin Cleric #2! I need to go change your brother, Hobgoblin Warrior from Strip #443, Panel 3.

An untitled webcomic frequently makes use this, frequently brining up often inconsequential side points from older comics and twisting their meaning and often connecting them to all kinds of other events. Recently it has been revealed that this is all the machination of the Illuminati of which Steve Jobs is a member.
Read the Alt Text on comic 576 of Xkcd. Now, go back and read comic 325.
- Also in Xkcd, the super soaker ends up reappearing a while later.

"Man, I forgot that was there."

- Another Alt Text nod from Xkcd: Alt Text in #616 referencing #150. There's also an Alt Text referrence to the elliptical reflector dish.
Appears a few times in Something*Positive. First is the reference to "I lava you," first seen on a note read by Davan and Nancy, and later repeated in a joke between Lisa and Gaspar.
- There's also the time when Aubrey and Kestrel entered a supply closet in the Nerdrotica building, where Aubrey stored some props from her less successful escapades. She is shown picking up a Cthulu mask, a reference to an earlier plot where she attempted to film a show called "My Neighbor Cthulu."
One strip in a Christmas-themed arc in Brawl in the Family, has King Dedede starting to go around stealing things set to a Filk Song from How the Grinch Stole Christmas. Now, going back a year...
- Matthew acknowledges that this strip is notably darker than standard Brawl in the Family fare, but check out the Alt Text and it'll point you to this one. Then all kinds of Fridge Horror pops up.
Unwinder's Tall Comics has a lot of these, sometimes resulting in Continuity Creep. For example, this comic references at least 5 different earlier strips.
Life and Death mentions the Gargle Blaster incident a few hundred pages later.^{[dead link]}
Many in The Inexplicable Adventures of Bob, with references to the Lint Mines of Dustworld, Bob's bottomless sock drawer, Molly wanting a pony for her birthday, the Grammar Squirrel, Molly's ridiculous fanfic crossovers (The Brothers Karamazov meet Harold and The Purple Crayon, or Gulliver vs. Mechagodzilla), etc.
Questionable Content's strip 1707 has a continuity nod from perhaps as early as strip 270, as Jeff spontaneously decided to draw Faye, Penelope and Hannelore with their old hairstyles. The nod may be to an even earlier hair style, if you count when Faye wore her hair with clips in colours other than red.
Made QUITE a few times in Triquetra Cats, which officially takes place in a probable alternate future of The Wotch, a short list includes the were creature jewel Wolfie and Katie use, (officially named in this timeline as the Samantha Stone, a reference to Samantha 'Wolfie' Wolfe) a descendant of Cassie Sinclaire named Circe, flashback panels showing Anne fighting Xaos, plus the plant that Cassie gives the love potion to is seen in a guest strip done by the Triquetra Cats team, this was later given a return nod in the Wotch where Glock mentions that "we need a full time force of people with expertise in mystical and scientific know how, and field agents prepped to deal with uncanny dangers, and entire SERVICE prepped to confront issues the public doesn't even believe in" in Triquetra Cats SERVICE is the name of the MIB type organization the main characters work for.
In El Goonish Shive, Grace's comment on The Princess Bride here is a reference to Susan's opinion of it here.
In Zokusho Comics Rotting Johnny assassinates a mage who was throwing around some powerful destructive magics. In a later issue, the Wayward Cross gets hired in place of the the mage to take out a group of goblins that have taken over a fort. At the end of that, one of the things they came to get from the fort is taken by the people who hired the Wayward Cross, so there may be further implications.
Homestuck is absolutely filled to the brim with in-jokes and references to past events. Often they become plot-relevant, but a lot are also just there for seasoned fans to pick out and to create a more cohesive work as a whole. (Andrew Hussie once claimed that there are very few pages that don't reference at least one other.) Strangely, there is actually an overriding plot reason for all of these, even the joke ones: circumstantial simultineity, in which similar events happen at the same paradox space time, is a real law of the Homestuck universe.
- To cite one of many, many examples, in Act 5 Act 1 Vriska complains to Aradia that she may as well rip her heart out of her chest with her super strong robot arm and pound away with it, because apparently it's up to her to feel emotions for the both of them. Later on, Aradia, in a robot body, does indeed rip her heart out and pound it against something. Much later in Act 6, the Autoresponder tells Jake that the brobot might as well rip its heart out of its chest with its super strong robot arm and pound away with it, because apparently it's up to the artificial intelligence to feel emotions for the both of them; later, it does indeed do this. There is absolutely no real meaning to these nods, but they're sure as hell fun to find.