How to make something go viral on the internet
When Courtney Dasher adopted a funny-looking, rescue dog, she had no idea that her beloved pet would become a high-earning, jet-setting internet star.
Tuna, a five-year-old chiweenie (a cross between a dachshund and a chihuahua), had been found abandoned on the side of a road in San Diego, southern California.
With a pronounced overbite, and goofy teeth that stick out, Tuna somewhat resembles a cartoon character. Ms Dasher thinks that he looks like Montgomery Burns from The Simpsons.
As a proud "mum" to Tuna, in November 2011 Ms Dasher started to upload photos of the chiweenie to her account on picture-sharing social network Instagram.
The 34-year-old says: "I had no intention to gather a large following at all, but almost immediately I noticed that people were commenting that he was making them laugh and bringing them joy."
Then on 12 December 2012, Tuna went viral on the internet, and he and Ms Dasher's lives were transformed overnight.
Unbeknown to Ms Dasher beforehand, Instagram had decided to put up three photos of the dog on its home page.
Within hours millions of people around the world were forwarding on the pictures, often superimposing humorous phrases onto the images such as "how I feel without make up", or "the underdog with overbite".
Tuna had overnight become what is known as an "internet meme" - something that spreads virally from one person to another via social media or email.
Such an internet meme can be anything that gathers mass interest, but is typically a funny image, video clip, song excerpt, or witty phrase.
In the case of Tuna, it has made him a celebrity, and brought a lucrative income for him and Ms Dasher, who a year and a half ago quit her job as an interior designer to focus solely on managing his affairs.
Los Angeles-based Tuna now has a best-selling book, and he visits bookshops across the US and overseas to meet adoring fans, more often travelling in his own seat on the plane. And a range of Tuna merchandise - from t-shirts to mugs - is available via his website.
While Tuna the dog's social media stardom was completely unplanned, savvy companies of all sizes are increasingly trying to create the next internet memes.
Get it wrong, and no-one will notice, but get it right, and a firm can get free, mass global promotion. It can connect with millions and millions of people.
But how easy is it to create a successful internet meme? How can you make something go viral in the internet?
Last year Swedish digital design company North Kingdom was approached by headphone firm Beats Electronics to try to create an internet meme to help promote the release of a film called Straight Outta Compton.
The movie is a biopic of the 1980s Los Angeles hip-hop band NWA, of which rapper turned businessman Dr Dre (real name Andre Young) was a founder member.
After leaving the band, Dr Dre went on to establish Beat Electronics, and the firm was going to release a new Straight Outta Compton headphone to coincide with the movie's release. Dr Dre was also a producer of the movie.
North Kingdom's idea was to set up a webpage called Straight Outta Somewhere, where people could type in their own Straight Outta caption, and then share it on social media.
So instead of the word "Compton", the deprived area of Los Angeles from where NWA originated, people around the world could type in the name of any city or town, be it Cape Town, in South Africa, Sao Paulo in Brazil, or Swansea, in Wales, UK. Users could also add their own photo.
Daniel Ilic, executive creative director of North Kingdom, says: "Just like the the movie tells the intriguing story about where NWA came from, Beats wanted the rest of the world to be able to do the same thing.
"The solution was to use the iconic Straight Outta insignia, and let the audience be creative with it."
After launching the website, it almost immediately caught people's imagination, went viral, and became a successful internet meme.
Within the first eight days last August, six million people had made their own Straight Outta caption, and there were more than 400,000 tweets mentioning the hashtag #StraightOutta.
Mr Ilic says: "We were very humbled by those numbers, and there were a lot of factors behind the tremendous success.
"To use an old saying, 'luck is when preparation meets opportunity'. The campaign showed that if you have empathy for your target audience they will engage.
"But there is never a certainty or guarantee in making something like this so popular and appreciated. [But] be brave and take risks."
One man who keeps a very close eye on the success, or otherwise, of memes created by, and for, companies is Jae Hong Kil, the chief executive of New York-based hedge fund Sentiment Alpha Capital Management.
His investment firm uses software to scan social media to see whether specific companies or products are picking up positive or negative "sentiment", and to what extent. Sentiment Alpha then makes investment decisions based on what it finds.
Mr Kil says: "To be a successful meme it has to be easy to accept and pass around by many people.
"For sure it has to have so-called 'coolness'. Therefore, to create a successful meme you need to understand who will be the targets, how many potential targets you have, and what they might enjoy.
"In addition, you have to be able to estimate how fast it can spread from one person to another."
Meanwhile, Steven Skiena, professor of computer science at Stony Brook University, Long Island, New York, says that despite all their best preparations, companies often still need some luck to see their meme plans go viral.
"Every company dreams of its message going viral," he says.
"However, there is a great deal of chance in what takes hold of the imagination and what doesn't.
"Perhaps the harder companies try to make their message vital, the less likely they are to succeed."