Rule 34 is an Internet meme which states that pornography exists for some topic of every conceivable sort. The idea is typically represented as fan art of typically non-sexual objects having sex. It may also consist of texts, animations, photographs, GIFs and any other medium to which the Internet allows opportunities for proliferation and redistribution.

History
The term Rule 34 was derived from an August 13, 2003, webcomic titled, “Rule #34 There is porn of it. No exceptions.” The comic was created by TangoStari (Peter Morley-Souter) to illustrate his surprise at viewing Calvin and Hobbes making fun of porn. Even though the comic itself fell into obscurity, the caption quickly became a hit on the Internet. The term has since been modified into various syntactic forms and has even been employed as a verb. A list of “rules of the Internet,” made on the website 4chan, contains Rule 34 in a list of similar tongue-in-cheek maxims, including Rule 63.

In 2008, 4chan users uploaded many sexually explicit parodies and cartoons depicting Rule 34; pornography in 4chan speak can be called “rule 34” or “pr0nz”. The Dictionary of Modern Proverbs states that Rule 34 “began appearing on Internet postings in 2008”.
As Rule 34 spread throughout the Internet, some mainstream media started to report on it. A 2009 Daily Telegraph piece included Rule 34 as the third of the “Top 10” Internet rules and laws. A 2013 CNN article stated Rule 34 was “likely the most famous” Internet rule to enter mainstream culture.
Fan fiction has spoofed events like the 2016 United States presidential election, the 2021 Suez Canal blockage, and Brexit.
Analysis
As researchers Ogi Ogas and Sai Gaddam explain, the adage struck a chord with so many individuals due to the seeming validity to anyone who has surfed the web. Ogas commented that since the 2009–2010 study, the consolidation of the porn market onto big market share video aggregators has decreased the visibility of the niche market videos. The platforms benefit mainstream content both directly by directing users to it and indirectly by putting small producers at a disadvantage who are not able to implement robust anti-piracy protection, calling into question the rule’s capacity to keep pace with market.
Cory Doctorow sums up, “Rule 34 can be viewed as a form of indictment of the Web as a cesspit of freaks, geeks, and weirdos, but through the cosmopolitan lens, speaks of a certain sophistication—a gourmet way of life.”
John Paul Stadler concluded that Rule 34 demonstrates the codification of paraphilias into social identity structures.
Variations
The original rule was restated and rephrased as it went viral on the Web. Some popular variations drop the original “No exceptions.”
“Rule 34: There is porn of it.”
“Rule 34:If something exists, you can bet there’s adult content of it
“Rule 34: If it exists, or can be conceived, there is Internet porn of it.”
“Rule 34: If you can imagine it, it exists as Internet porn.”
“Rule 34(r): If it exists, there is a subreddit dedicated to it.”
Corollaries
“Rule 35: If you can’t find porn, don’t worry, someone will make some.”
“Rule 36: There’s always going to be more fucked up shit than whatever you’re currently looking at.”
“Rule 63: For any given male character, there exists a female counterpart to the character and vice versa.”