When Bryan Bundesen posted a photo of his sister’s kitten on Reddit, little did he know that the odd-looking feline would become one of the internet’s best-known celebrities.

The sourpuss image has been replicated thousands of times with grumpy captions posted on websites and social media pages. She has a manager, a successful merchandising franchise, a Grumpy Book, a Facebook page with almost seven million likes and nearly 250,000 followers on Twitter. Now there’s a movie, Grumpy Cat’s Worst Christmas Ever, to be broadcast on the cable TV network, Lifetime.

"Grumpy Cat is phenomenally successful,” says Karen North, a professor of social media at the University of Southern California's Annenberg School.

"One of the most popular activities online is displaying images with snarky captions. People take an event or a piece of media or an image on a digital platform and they mash it up, or they parody it or they adapt it."

For this, Grumpy Cat is the "perfect image”. Her 15 minutes of fame has transformed her into a marketing and entertainment powerhouse. She is an internet celebrity that now rivals other iconic figures such as Garfield and Hello Kitty. But is she immortal?

When I met Grumpy Cat, real name Tardar Sauce, she was lapping up the attention of admiring fans at the SXSW conference in Austin, Texas.  The music and pop culture event was the perfect venue to highlight the extraordinary allure of this unlikely star.

Her owner, Tabatha Bundesen, explained that Grumpy's facial expression could be due to feline dwarfism, a condition that means she is petite in stature, but otherwise a normal, playful cat.  But there is nothing normal about the internet obsession with this animal.

"She truly is special,” says Ben Lashes, Grumpy Cat’s manager.

"She’s the sweetest, grumpiest cat that there is. Even walking down the street we get recognised by people.  They run from down the block to get a picture."

Nine lives?

When Lashes was brought in to manage Grumpy Cat, he already had experience representing internet memes. He also acts on behalf of Keyboard Cat, the first internet feline, who became famous after a video, originally made in 1984, was posted to YouTube in 2007.

Lashes, a former rock musician, specialises in cats but also manages Success Kids, Scumbag Steve and the Ridiculously Photogenic Guy. He describes himself as doing for internet celebrities what Brian Epstein achieved for The Beatles. The analogy will be judged in the fullness of time, but Lashes is confident that pop culture memes are here to stay.

"In the last four years I’ve gone from being laughed off the phone when I try to talk to somebody about a famous cat to not being able to answer enough phone calls in a day,” he says.

"Culture isn’t that different to how it’s always been, it’s really the method of distribution that’s changed."

Lashes believes that the internet, being a great equalizer, has put the power of choice into the hands of the consumer. No longer do people have to rely on the corporate world, such as Hollywood studios, to create new characters.

"You get enough people who just decide to love something just for what it is, without being told and that can be a more powerful fan base than any fan base that you’re trying to pay for. It is the same as drawing three circles and having them turn into Mickey Mouse. As long as there are people that care about these things and are passionate about it, it can keep continuing to grow."

Taking the Mickey

Comparing Grumpy Cat to one of Hollywood’s most enduring cartoon characters may be a stretch, especially when it comes to longevity.

"What makes Grumpy Cat strong is that she expresses grumpiness – but it is also what limits her,” argues Amy Nicholson, chief film critic for the LA Weekly newspaper.

"Mickey Mouse can do a lot of things. He can captain a steamboat, he can goof around with Minnie, he can play with a dog and he can conduct an orchestra. Grumpy Cat can't really do anything besides frown."

The entertainment world is usually quick to drop a character as soon as it becomes clear that it is waning in popularity. There is no sign of the writing being on the wall for Grumpy Cat yet, but the time may come.

"For every meme category there’s one meme that will stay,” believes Nicholson.

"We’re already pretty full of a hundred basic memes that cover every human emotion and those will last as long as the trend lasts.  Then I don’t think many memes will come along to replace it."

Only time will tell whether internet celebrities with be with us for the long haul, adds North.

"To the extent that they can create an enduring image, like Hello Kitty or Garfield, is debatable.” 

"The world audience is somewhat fickle. Most of these characters don’t live on for a long time.  They’re a fad. That’s why agencies are coming in to try to manage the brand." 

The next big meme

The corporate world, and that includes the management team behind Grumpy Cat, will no doubt squeeze every last computer click out of this new breed of celebrity.

Lashes sees his role as the internet kingmaker.  He acts for the people who own the rights and materials behind the memes and helps them expand their brands. He believes the trend has only just started and shows no sign of petering out.

"To kids these days who’re growing up with phones in their hands before they can speak, the characters are all the same. It doesn’t matter which screen they discover them on."

Lashes is not alone in attempting to capitalise on online content. It is a growing and profitable business which has attracted the attention of the big players in the business.

YouTube has come up with its Creator Playbook which includes a section outlining what it calls the Fundamentals to Create Content People Love. In effect, it is a how-to-guide for would-be viral content providers to help them dream up an image for the next big meme.

"I think it’s going to be really interesting to see how pop culture uses something that is really, in essence, free and user-generated and tries to use it to make money,” says Nicholson.

"Grumpy Cat can sell t-shirts but when it comes to a larger scale, when people feel that they are being sold Grumpy Cat, rather than they created Grumpy Cat, I’m not so sure that it will work out for them. 

"If it does, you’ll see a lot of people trying to pull it off."

If you would like to comment on this story or anything else you have seen on BBC Culture, head over to our Facebook page or message us on Twitter.