I think cats are going to take over as the world's supreme beings soon,” Ben Huh says. As the owner of six duplicitous, whiskery tyrants myself, I've long suspected as much, but Huh arguably has more reason to fear the feline apocalypse, being the recipient of more than 8,000 moggies every day. This is the number of humorous cat-themed photographs - give or take a few dogs, walruses and goats - that are submitted to his Seattle-based website, icanhascheezburger.com.

If you have never seen an icanhascheezburger picture - the standard shot features a cat with a caption in bold white lettering, misspelt in a language termed “lolspeak” or “pidgin kitty” - you probably don't own a PC. The rise of the site has to be one of the most meteoric in web history.

At 2am, January 11, 2007, a between-jobs Hawaiian computer geek called Eric Nakagawa received an instant message from his girlfriend, Kari Unebasami, linking to a picture of a chubby-cheeked grey cat on the humour site Something Awful, accompanied by the caption: “I Can Has Cheezburger?” Both thought it was funny, bought a domain name in tribute and set up a blog asking people to send in their cat pictures with similarly semi-surreal, childishly spelt captions.

By early summer, Nagakawa was receiving 500 e-mails a day and in September that year accepted an offer to sell the site for $2 million to Huh, a 35-year-old journalist. This March, icanhascheezburger reached No 8 in a UK newspaper's 50 Most Powerful Blogs list. Last week, it was recording about 5.5 million hits every day.

It might be presumed that entertainment doesn't come much dumber than placing an idiotic statement next to a picture of a pet, but constructing a LOLcat (aka “laugh-out-loud cat”) is a fine art, very different - though not necessarily any less nuanced - than, say, the classic New Yorker magazine-style pet cartoon. The best cheezburger photo-caption combinations manage to sum up a dumb deviousness that's quintessentially feline (a ginger kitten on its hind legs, captioned with “I baked you a cookie...but I eated it”) or convey the sense that, in their hearts, cats believe they can outperform human beings at their own tasks (a cat on a dashboard, accompanied by “GPS cat sez you lost”).

The poetic placement of the words is crucial, too. Having selected a photo of one of my own cats for my first LOLcat photo this week - of my mouthy black cat, Shipley, sitting next to a promotional CD by the band Dogs, staring knowingly at the camera - my verseophobic brain stumbles. I finally opt for “A&R kitteh” in the top of the pic with “hates ur demo” at the bottom left.

Time magazine has called icanhascheezburger “no longer a subculture, just the culture”, but it still retains some very cultish aspects. Huh insists that, despite the recent founding of a lolspeak dictionary, there are no real rules, but in its peculiar, heightened cat reality, certain customs have evolved. “Ceiling cat” is a recurring god figure in LOLcat photos. “Basement cat” is his satanic adversary. Cheeseburgers, perhaps predictably, are the ultimate feline delicacy.

The genius of the site is managing to be mainstream yet making its users feel as if they are part of an exclusive club. The childish language is often mistaken for the textspeak of Generation Y, but its appeal goes far beyond millennials.

“I spend about four or five hours a day dipping into icanhascheezeburger,” says 69-year-old Ann. “I do find lolspeak leeching into my everyday conversation. It is difficult not to greet everyone I see with (the common ichc cat hello) ‘ohai'!”

In just over a year, pidgin kitty has spread far beyond the cat-loving community. LOLVogue, one of the most popular features on the American gossip site Jezebel, regularly recaptions fashion magazine photo shoots, attributing crude, catlike thoughts to Vogue models.

Any Google search for George W. Bush photos will turn up several hundred derogatory LOLcaptions. Icanhascheezburger has recently branched out with a dog equivalent, ihasahotdog, but while Huh claims that “a lot of the people who come to the site don't even like cats”, the uniquely prissy feline ego seems to be the key ingredient. “I think cat pictures are popular because cats have such an amazingly wide range of emotions. They can love you one minute and absolutely hate you the next.”

If porn and shopping were the two dominant themes of the first internet era, it's possible that, in these troubled financial times, porn and cats - though not, thankfully, together (icanhascheezburger has strict moderators) - are becoming the two dominant themes of the second. The cat picture has become the ultimate virtual livener during a hard day at the office and numerous stories circulate of employees being sacked for spending too much time looking at sites such as icanhascheezburger, stuffonmycat.com, catsinsinks.com and catsthatlooklikehitler.com. “It's impossible to be in a bad mood when you see a picture of a kitten doing an impression of a drunk human,” says Matthew McCherry, a cheezburger site obsessive and charity shop manager from South London.

My own cats are crafty enough to dictate what time I get up in the morning and the way I arrange my house, so it's perhaps logical that they dominate my web use as well. “It doesn't surprise me that cats have taken over virtual reality,” says Celia Haddon, author of The Joy of Cats. “They can adapt to all sorts of modern life. They are probably, after humans, the most successful species.”

So what does all this signify? From a slightly hysterical science-fiction standpoint, one might look at the eerily high percentage of icanhascheezburger pictures featuring cats on keyboards and fear slightly for our future as a race. It can definitely be said that cat domination of the internet is a reflection of the elevated role that pets are playing in our lives (“More and more people are treating their cats like children and that's reflected in icanhascheezburger,” Huh says).

At the very least, the webcats are more confirmation of Alan Coren's theory that cats - along with Nazis and golf - are one of the three most reliably funny subjects on Earth.

“Cats obviously think they're our superiors,” Haddon says. “They don't defer to us. I'm convinced that they think we're a seriously incompetent species. Why is that funny? I am not sure, but it is.”

Tom Cox: littlecatdiaries.blogspot.com

I Can Has Cheezburger: A LOLcat Collekshun is published by Hodder, £9.99

Times recommends

• The Boxing Day tsunami: five years on
• What took place in 2010...
• Can you really cure a hangover?