Tracing the exact birth of Caturday involves multiple threads. The domain "caturday.com" was registered on April 30, 2005, and Time magazine's Lev Grossman placed the concept's roots in early that year after reader feedback corrected his initial estimate5. One of the first non-4chan uses of the name was a Blogspot blog called "Caturday" created November 16, 2005, by a New Hampshire user named Sharyn who posted stories and photos of her own cats rather than LOLcat macros4.

The meme tradition itself, posting LOLcat image macros on Saturdays, took root on 4chan's /b/ board1. A LiveJournal community launched on February 5, 2006, with the rallying cry "Post some fucking cats!"3. Urban Dictionary's first definition appeared on October 24, 20066, and one of the earliest archived Caturday threads on 4chan dates to December 12 of that year4.

Caturday kicked off the LOLcat movement that turned cats into the defining animals of internet culture. The weekly tradition fed directly into I Can Has Cheezburger, one of the biggest humor websites of the late 2000s2. LOLcats spread from imageboards to college campuses and mainstream news within a year of ICHC's launch8.

The term "lolcat," which grew from the same culture, was a runner-up for the American Dialect Society's "Most Creative" Word of the Year, losing to "Googlegänger"5. The #Caturday hashtag itself became a weekly fixture on Twitter, trending most Saturdays as of 2021 with users proudly showing off their cats1.

Putting funny captions on cat photos didn't start with the internet. Photographer Harry Whittier Frees created staged photos of kittens in human situations in the early 1900s, including the well-known "Five O'clock Tea" image2. Caturday gave this long-standing impulse a digital home and a weekly schedule.

When 4chan users adopted Saturday as cat posting day, the practice quickly developed its own language. Lolspeak wasn't random misspelling. It followed consistent internal rules for conjugation and spelling, blending baby talk, internet slang, and references to other memes2. The format proved durable enough that volunteers translated the entire Bible into lolspeak at lolcatbible.com, complete with guides on proper translation technique2.

The LiveJournal community that formed in early 2006 showed how seriously early adopters took their weekly cat holiday3. Rules demanded images in every post, required image counts under cuts for dial-up users, and banned cat-themed icons, colorbars, and layouts. Animal abuse images meant an instant ban, and disabling comments got your post deleted3. The community described Caturday as "the greatest holiday on the internets" and grew to over 2,196 members6.

I Can Has Cheezburger's 2007 launch took the concept far beyond imageboards. The site reportedly sourced its first image from the Something Awful forums and quickly became one of the most popular humor destinations on the web2. LOLcat culture spread to college campuses, mainstream blogs, and news outlets within the year8.

By the 2010s, most people posting #Caturday had no connection to 4chan or lolspeak. The tradition simplified: share a photo of your cat on Saturday1. The captioned image macro format faded outside of intentional throwbacks, but the core ritual endured. I Can Has Cheezburger evolved into a broader funny-animal content hub that still publishes daily9.