Shortly after its launch, Facebook ripped like wildfire through American Ivy League universities, hundreds of thousands of eager college students signing up every day. What it offered seemed almost entirely new: the ability to connect with friends, upload photos, organise events, and most importantly stalk crushes, friends or prospective friends.

But it wasn't quite the first. "MySpace was the first chance the world had to see the power of social media," says social media expert and entrepreneur, Jodie Cook. "It demonstrated the potential for it to take over your life, as people trawled the internet for the perfect background picture and took hundreds of selfies before choosing their profile picture.

social apps

"It opened up a whole new world which perfectly coincided with the rise of reality TV - where everyone wants to be famous. It got people familiar with the concept of knowing people online who you didn't actually know in real life."

Yet Facebook is the social platform that has proved the most enduringly successful to date, after the rapid demise Friendster, the first ever social network, and the short-lived success of Myspace.

This Wired article features a discussion between the members of the group that pioneered Facebook. It details each choice that sculpted the platform into what it is today: the decision to allow people to upload more photos than simply a profile picture - would people respond well to that? (They did.) What about the newsfeed? The moment it was introduced, there was outcry.

Critics of the feature said it felt like they were being monitored, with every update broadcast to their followers. (Before, you had to visit someone's page to track updates.) But interestingly, even as public cries for its removal resounded, engagement was soaring: people were checking the site at much higher frequencies than before. Suffice to say, the feature remained. 

Another crucial decision was the introduction of the like button - a feature which these days is so second-nature its existence seems to have predated humanity itself.  

Each decision further ramped up 'engagement' and further ingrained the act of social-media-checking into the architecture of our daily existence. Sharing, scrolling and stalking became accepted, everyday behaviour.

Over 10 years, Facebook membership has swelled to 2.27 billion active monthly users, meaning that if it was a nation it would be the largest on Earth. But despite this, predictions of its demise have been whispered, and sometimes shouted, for years.

The number of young people signing up for and using Facebook regularly has been in decline for some years now, with other services such as the Facebook-owned Instagram and Snapchat, along with newcomers such as Tik Tok (formerly proving more popular with Gen Z. 

But why is this happening and should Facebook be worried? The lifecycle of a social app can be streamlined into three distinct stages: first come the kids, then the brands, then the grans. 

The kids

Will Francis is a social media consultant who was editor at Myspace before it folded. He believes that the popularity of a social media app is always likely to be cyclical, but that early success is defined by a platform that appeals to young people in some way.

"It starts with the people who are most likely to pick up and try new things, which are teenagers," he says. "At that age you are so open minded and susceptible to a network effect."

A network effect is when you are attracted to a certain platform or product because others are using it too. It's particularly present in school and college age populations because they spend so much time around their peers within close-knit social structures.

This explains why Facebook spread so rapidly through college age adults, and why for services such as Snapchat and the lesser-known platform, Tik Tok, the earliest and most rabid adopters are tweens and teens.

The brands

But a new social platform can attract millions of teens and be hailed as revolutionary within the media industry - Snapchat being a prime example - yet still not be making any cash.

"What happens is the company realises that their costs are going up and they're haemorrhaging money," says Francis. And despite the extensive user base of such apps, teens can bring subversive cool, but in terms of spending power, they're generally more limited. "It's a bit of a long-term play, marketing to 15-year-olds," Francis adds.

Meanwhile, early investors in the platforms and shareholders put immense pressure on the platform's management team to start making money and providing returns on their investment. 

It's this predicament that defines the next stage in the lifecycle: the brands.

Platforms arrive at the point that in order to make money they have to both bring brands on board and broaden their appeal to a wider demographic.

According to Francis, this prompts social platforms to actively court older users, while in parallel there is also a natural phenomenon where usage spreads upwards to different age groups - whether by word of mouth, media attention, or just friends and family.

But bringing brands on board can be a tricky balancing act.

"This point often coincides with when a particular platform becomes less interesting for users," says Cook. "It puts the onus on brands to keep being creative in how to reach users on a more personal and less corporate level."

This isn't always a feat that the platform or brands can pull off, illustrated, for instance, in the tantrums thrown online when certain new formats, layouts or features are trialled within different social platforms. Ironically, because of social networks themselves, users can now respond - sometimes ferociously - to change. 

Almost all of the major platforms have ended up reversing controversial changes shortly after their introduction. Most notably, Snapchat ended up pulling back from a decision that more aggressively blended branded content with that of friends and family, leading Kylie Jenner to tweet 'Am I the only one who never goes on Snapchat anymore?' and instantly wiping billions off the stock market valuation of the platform. Another is when Instagram trialled a new 'home' feed and quickly backpedalled due to an outcry. 

It's widely agreed that brands can negatively impact on the user experience, but is the loss of the 'cool factor' also instrumental in a social platform's demise?

Francis says this is something that Facebook has risked in its embracing of the business strategy.

"Now there's local listings and recommendations and business listings. And there is something inherently uncool about that," he says. "You basically become the 'mom' version of Yahoo, do you know what I mean?"

And it's in this way that introducing the brands can lead to the loss of new, young audiences. A case in point is Myspace, according to Francis. 

"The new people who were turning 13 and were eligible to sign up to the platform were looking at it and going, 'This looks shit'," he says. "This looks kind of like a primetime advert, this doesn't look like a cool, grubby place that I shouldn't really be in. My parents wouldn't disapprove of this, this looks like somewhere my dad would hang out."

The grans

This brings us to the final stage. Although most platforms end up widening their demographic appeal somewhat, Facebook is the only social platform that can be said yo be genuinely popular with grans. "Facebook is the ultimate example. It's completely demographic-less," says Francis. "It's not like a young-person thing, it's everybody's thing. My mom, who is in her mid-70s, spends a lot more time on Facebook than me."

At the other end of the spectrum is a platform like Yik Yak, the location-based 'anonymous Twitter' that never became popular with people outside of highschool and university and due to a series of unpopular format changes ended up shutting down.

However, popularity at the beginning of an app's lifecycle doesn't necessarily determine longevity. Google+ had one of the fastest take-ups of any platform, according to Cook, but has recently shut down.

But the number of social media platforms have proliferated, and with it a fragmenting of the market. A mindset has prevailed that one social media platform doesn't need to provide us with everything. 

"On a very broad scale, Facebook is used for keeping in touch with friends, Twitter is used for keeping in touch with strangers and celebrities, Instagram is used for becoming your own brand and LinkedIn is for your career and networking purposes," says Cook. "However, the lines are increasingly blurred between them. Essentially, all social media platforms offer ways of sharing your day-to-day and portraying your professional and personal life as you want others to see it."

A fragmentation effect has also precipitated the rise of niche networks that have some of the most ardent fans. For example, Reddit, Tumblr, Pinterest and Tik Tok have all attracted specific, but very engaged demographics. 

Social media expert, Jemima Gibbons, advises her clients: "You've got to find your niche when you're growing: the niche audience that you can attract at the beginning and then you grow from that. The platforms that are doing well are the ones that have a hardcore following in one particular group, or maybe across many different groups. But it's that hardcore, passionate following that's going to drive your network."

At the other end, trying to be everything to everyone can also prove a fatal misstep. "Facebook and Twitter and a lot of other platforms have become very cluttered," says Francis. "They've tried to do lots of things and it made that classic mistake - and it's the mistake Myspace made too - of trying to be everything to everyone."

"By the end of Myspace, there was a comedy channel, horoscopes, local listings," he continues, "I mean, they tried to be the bloody internet. It was ridiculous - it became a joke internally. And they tried to diversify and capture so many audiences. If they had just remained a cool place to connect with grungy local bands and stuff, it would still be here."