How two whizz-kids made a billion dollar app in 551 days

It's all a question of momentum. That's the difference between the millions of online ideas that simply melt away and the handful, like Instagram, which keep rolling and growing until they deliver the life-changing pay-day of which every start-up founder dreams.

The photo-sharing network first appeared on Apple's App Store on 6 October 2010. It was the same day David Cameron first addressed a Tory conference as Prime Minister. But whereas the Prime Minister's fortunes have been mixed in the short time since, Instagram's rise has been relentless. It had a million users within two months. And it has kept expanding since.

Thanks to Facebook's $1bn (£630m) buy-out, Kevin Systrom and Mike Krieger have become vastly wealthy overnight while still in their 20s, but their discovery of such a winning formula was a drawn-out process. On the road to honing the Instagram app, they left behind a series of failed projects. Mr Krieger worked on an app that aimed to counter Seasonal Affective Disorder (SAD) by offering sufferers the rays of sunshine in photos posted by users living in warmer climates.

Meanwhile Mr Systrom, who had formerly worked for Google, set up a location-based web service called Burbn, which didn't go exactly according to plan. Burbn never got past a few hundred users, but it allowed Mr Systrom – who, according to the website TechCrunch, raised $500,000 in seed funding for the project – to develop his programming skills, just as the sunshine project was an essential learning curve for Mr Krieger, an engineer and user-interface designer.

Those users who had signed up for Burbn mostly used it to upload photos of their visits to bars and cafés. Mr Systrom recognised that he was on to something and Burbn duly became the skeleton model for Instagram. The Instagram app allows users to take photos using a variety of filters, with names such as "Toaster", "Lord Kelvin" and "1977", giving their images a distinctive retro look. The formula has proved globally popular. Crucially, the pictures can be shared across a host of social-media sites, from Facebook and Foursquare to Twitter and Tumblr.

By last June, the app had five million users and it has added to that number at a rate of about two million a month. The surge in interest was fuelled by celebrity endorsements from Justin Bieber, Kim Kardashian, Snoop Dogg and then Barack Obama, who all took out accounts. Bieber in particular was a huge driver of traffic from his army of 20 million followers.

When the Facebook founder Mark Zuckerberg clinched his $1bn purchase of the 18-month-old start-up this week, Instagram had a user base of 30 million updating five million photos every day.

The size of the deal brought gasps of astonishment even in a world that has witnessed the buyouts of MySpace (bought by News Corp for $580m in 2005), YouTube (bought by Google for $1.65bn in 2006) and The Huffington Post (bought by AOL for $315m in 2011), Facebook's reasons soon became clearer.

Until last week, when it released an Android App, Instagram was only available on Apple devices. The development has given the application an even greater momentum. Within 24 hours of being available on Android it found one million new users. After six days it had registered five million Android downloads.

So, does the Instagram deal herald a new dot.com boom? Probably not. Mr Zuckerberg, who will allow Instagram to remain as a separate brand, was making his first major acquisition. Among start-ups in the UK, Mind Candy – the company behind the Moshi Monsters brand – seems best-placed to enjoy a big pay-day. But the market remains cautious. Instagram might be worth $1bn this week. But it could turn out to be a fad.

Sleeping around: My moment of truth happened at university

Even during my hedonistic teenage years, somewhere in the back of my mind I had a "checklist" for my life. I'd envisioned meeting the man of my dreams at around the age of 29, and marrying by 30ish.

I did meet the man of my dreams at the age of 29, but I guess we took a wrong turn somewhere, and our relationship ran into a ditch. But if there is any truth in the saying "life is what happens when you make other plans", I think that the same logic would also apply to love.

Sexually, I was an early bloomer and a pretty wild teenager. I had an S&M relationship with my 24-year-old French teacher and held naked make-out parties in my swimming pool on weekends.

But, although I was adventurous and curious, I was much more concerned with having all the right moves when it came to pleasuring the boys than pleasing myself. Because of this, until the age of 19, I'd never had an orgasm (although I did some Oscar-worthy faking).

My moment of truth happened at university, when I went to see a sex educator speak candidly about self-love and show a video of women touching themselves.

The next day, I went to the chemist and bought a Hitachi Magic Wand vibrator (saying it was for "neck pain"), locked myself in my bathroom and came out 45 minutes later a new woman.

Once I realised that I had to take responsibility for my own pleasure, sex and relationships in my twenties were all about experimentation. There were the one, two, and three night stands, the lesbian flings, the scuba diving instructor who gave me my first orgasm through oral sex, the sex parties, and the man who taught me that men could have multiple orgasms too all discovered through random, amazing encounters.

While worrying about protecting myself from pregnancy and STDs, as I approached my mid-twenties I realised that I was also protecting my emotions perhaps a bit too well.

So I let someone in, and experienced my first real heartbreak. But even then, I got over it quickly, since relationships then were mostly about self-discovery and sharing experiences with my friends, with the men in supporting roles.

I'm glad that I did things this way round, before I had children or a husband.

Now that I've just hit my thirties, I'm ready to confine my wild bedroom antics to one (very lucky) man, and am convinced that my sexual exploration will make me a much better partner, both in and out of the bedroom. I'm more stable, confident, and happier than ever.

But dating is harder, because there is more on the line. I'm still undecided about children, but the reality of the biological clock means that I feel I have less time to waste on the wrong person, just in case I do decide to have kids.

Maybe this is because women put too much pressure on themselves to have it all. Despite the fact Cameron Diaz, 36, and Jennifer Aniston, 39, are gorgeous, rich and have amazing careers, they are the subject of constant headlines asking why they haven't already found "the One".

Meanwhile, everyone wants to know who will be lucky enough to finally land 47-year-old George Clooney, instead of questioning the wisdom of going out with a guy whose most intense emotional connection to date seems to have been formed with a pot-bellied pig.

But I think we could all learn something from George. He doesn't care about convention, and is blazing his own trail. I'm hoping to do the same, live my life and eventually find someone who can give me a mix of great conversation and swinging-from-the-chandeliers sex that will be as fantastic at 60 as it is at 30.

Fact: players are too big for own good

The extraordinary transformation from the stamina-based rugby of the game's amateur era to the physically combative version served up by today's professionals is illustrated by The Independent on Sunday today in a unique comparison between this year's Lions tour and the trip to New Zealand in 1971.

The desperate plea for change made by Lions doctor James Robson at the end of the tour to South Africa in July, when the Scotsman warned that players were getting too big and muscular for their own good, is borne out by our exclusive statistical and subjective analysis. By comparing key indicators between the Second Test of the 1971 tour in Christchurch and the Second Test in Pretoria in 2009, the anecdotal theory that rugby has become a collision sport for muscular hulks is revealed as hard fact.

It follows a week of debate over injuries and the laws at the International Rugby Board's interim meeting in Dublin, and questions the whole approach to player safety in the contact areas of scrum, tackle and breakdown as well as the battles in the air.

We teamed up with rugby website ESPNScrum.com, TV channel ESPN Classic and statistics experts Opta Index to analyse complete footage of the 1971 and 2009 Tests side by side. Though the essential facets of the game are broadly similar, there were obvious developments in how the matches were played out, with much more reliance on power and contact. "Looking at the stats and watching the matches pointed to a hell of a lot more collisions in the game," said Graham Jenkins, editor of ESPNScrum.com. "What is quite clear is that players are taking the ball into contact rather than shifting it like they seemed to do in the 1970s."

There are fewer scrums now but the "hit" on engagement comes with markedly more impact. In 1971 the forwards mustered immediately over the mark and every scrum was completed first time. Today's packs are heavier by a combined 35 stones – on average, a 2009 Lions back weighed more than a forward in 1971 – and despite the "crouch, touch, pause, engage" protocol, scrums are often collapsing or being reset, with the attendant risk of wrenched shoulders and necks. The aerial game of 2009 – leaping high in the line-out, and jumping to catch restarts and garryowens – has no parallel in 1971, when feet rarely left the ground, and never by much.

Some other specifics are just as compelling. There were more than three times the number of tackles in 2009, and the tackles in 1971 were clearly of less impact. Only one, when the All Blacks' Bryan Williams ran into Gerald Davies near the end, was of the head-on variety which today routinely smashes the opponent backwards; the rest in 1971 were side-on or from behind so the tackled player was able to fall forwards in greater safety. In 2009, Brian O'Driscoll's tackle on Danie Rossouw without the arms wrapping round led to both players going off injured.

John Taylor, 1971 Lions flanker and ESPNScrum.com columnist, said: "Player by player now the guys make many more tackles. We didn't expect Barry John [at fly-half] to make any. There were fewer rucks in that particular match in 1971 than our other Tests, but when you did ruck you had to commit more forwards because you weren't allowed to handle the ball once it was on the floor." Nevertheless, the clattering "clear-out" collision by the Springboks' Bakkies Botha which dislocated Adam Jones's shoulder in Pretoria was nowhere to be seen in Taylor's day.

Davies, a wing in 1971 and the manager this year, called the 2009 match "brutal" and Taylor concurred. "With the size of the guys and how dynamic they are now, the intensity is shuddering. The sheer physicality of the Second Test this year was incredible."

As for entertainment value, that beauty remains in the eye of the beholder. The stop-start nature of the 92 scrums and line-outs in 1971 is countered by the match being done and dusted 20 minutes quicker than in 2009, with fewer stoppages for injuries and substitutes.

'Cuddle drug' may be the new Viagra

It is the chemical that has been described by women as a "cuddle drug". Now scientists have discovered that its effect on men is more rampant and long-lasting than just the desire for a quick hug.

Oxytocin, a hormone traditionally used to induce labour, is as sexually arousing to men as Viagra, according to new research.

Studies conducted in the US found that a married man who sniffed a nasal spray containing oxytocin twice daily became more affectionate to friends and colleagues and recorded a marked improvement in his sexual performance.

According to the actual breakdown of results, the man's libido went from "weak to strong", while arousal went from "difficult to easy". Ego certainly wasn't hurt either: sexual performance, according to feedback from his wife, was classed as "very satisfying".

Scientists at the University of California believe the findings provide strong support for the idea that oxytocin improves sexual performance and, unlike Viagra, remains a chemical glue within the brain to cement relationships between people. Just how it works is not clear, but some studies have suggested that oxytocin levels rise naturally during arousal. The hormone is also thought to interact with the dopamine system, which is involved in the rewarding aspects of sexual activity.

Dr Mike Wyllie said: "Given the number of erectile-dysfunction patients who don't respond to drugs like Viagra, there is a great medical need for a new class of drug; this case study suggests there is a basis for optimism that this is achievable. Assuming positive clinical trials, a drug based on this approach could achieve blockbuster potential."

Oxytocin is produced mainly in the hypothalamus region in the brain, and has been most widely studied in women. It's released during labour to dilate the cervix and boost contractions, and also triggers the release of milk in the breasts. More recently it has been shown to have wider effects on behaviour, including boosting trust, co-operation and bonding, and it has been investigated for a number of conditions including anxiety and autism.

The new study, "Dramatic Improvement in Sexual Function Induced by Intranasal Oxytocin", was reported in The Journal of Sexual Medicine.

Oxytocin's power was first recognised in 1979 when virgin female rats whose brains were injected with the hormone began to display maternal behaviour. Since then, several hundred research studies have been carried out, shedding light on the hormone's role in the early stages of sexual passion and in the process of mother-child bonding after birth.

100 things to do before you die, 1-50

Dave Freeman died this month, having worked his way through half the list. Here’s your chance to find out if you’ve done any better.

Click HERE or on the image to see his definitive list of life-changing experiences in pictures

Taken from the book, 100 Things To Do Before You Die, by Dave Freeman and Neil Teplica

Click HERE to view 100 things to do before you die, 51-100

Lineker blames £25,000-a-year school after son fails to make grade

Most schools would expect to deal with a handful of troublesome parents at this time of year, when the exam results season understandably causes emotions to run high. But not all of them have to cope with the ire of a former England football captain.

Gary Lineker was embroiled in a very public row with his son George's private school last night after the 18-year-old failed to get into university. The Match of the Day presenter and former England striker had chosen to send his son to the exclusive £25,000-a-year Charterhouse School in Surrey, which recently ditched A-levels in some subjects to allow pupils to do the new "Cambridge Pre-U" exam.

The qualification is said to be tougher by education traditionalists, as it eschews coursework in favour of an emphasis on the end of year exam.

Lineker said: "We don't know what's going on at the moment. [George] did the Pre-U and they seem to have been marked much harder than the A-level papers. It's all a bit frustrating as it is the first year the Pre-U exams have been used so George has been used as a guinea pig. At the moment his university place has been withdrawn but we are hoping to find a way round this. We are all very disappointed."

George was more explicit about his alma mater on his Facebook page, saying: "Didn't get into uni... cheers school u massive knobbers!" He is now one of around 160,000 youngsters expected to miss out an a university place.

However, Charterhouse remained unrepentant about its decision to opt for the Pre-U. The Reverend John Witheridge, the school's headmaster, said: "We are delighted with our pupils' excellent results this year.... we do not comment on the performance of individual pupils."

Students who take Pre-U exams cannot resit them. Cambridge International Examinations, which sets the test, says it provides more time for "great teaching and deep thought" because all of the exams take place at the end of a two-year course.

The row comes at a time when Education Secretary Michael Gove has paved the way for an expansion of the Pre-U into the state sector.

George Lineker had been planning to study business at Manchester University, where he had been offered a provisional place but had to obtain the equivalent of three B grades at A-level. Last Thursday he learned he had failed to do so.

He was spotted on a week-long holiday to Tenerife only a few weeks before his exams, and in March was pictured on a night out with Sophie Reade, a 21-year-old glamour model who won the previous season of Big Brother.

Alex Ferguson delighted David Beckham will wear Manchester United shirt

Sir Alex Ferguson could not be more delighted that David Beckham has agreed to wear a Manchester United shirt again.

Eight years after he left Old Trafford for Real Madrid, Beckham will fly back to England next week to play in Gary Neville's testimonial match against Juventus.

Confirmation of Beckham's participation completes the famed 'Class of 92' that emerged through the Red Devils youth ranks at much the same time and all went on to become United stars.

Ferguson has already guaranteed Ryan Giggs and Paul Scholes will be involved despite their presence in the United squad for the Champions League final clash with Barcelona on May 28.

And the United boss has promised further big-name representation to provide the appropriate tribute to a player who quit in February after amassing 602 appearances for the Old Trafford outfit.

"With David Beckham coming, along with Nicky Butt, Phil Neville, Scholes and Giggs, it will be a fantastic occasion," said Ferguson.

"It is great to reunite these players together.

"There is no question they created a magnificent spirit in the place when they first arrived in the team.

"It helps us too because Gary's service to the club deserves a good representation from Manchester United.

"He has been a fantastic servant and I hope he gets the crowd he deserves."

It will be a novel experience too given Neville has confirmed all power used during the game will be matched by 52 windmills across the country powered by Ecotricity.

Neville has become more associated with sustainable projects in recent years and has just had planning permission granted for an 'eco home' just north of Manchester.

"I have recognised in the last two or three years the need to make personal changes in my life," said the former England star.

"Reducing my environmental impact is going to be a five-year transition for me and my family but with planning permission for my new eco-home being granted and my association with wind turbines, I am on track to complete this journey.

"I believe sport crosses all boundaries and plays a significant role in many people's lives.

"From my perspective, we have to look at the effect sport has had on other issues over the last 20 years to see that when sport comes together with society, positive actions can happen."