Apple's wasn't the first app store, nor when it launched, was it the biggest. When it went live in July 2008, alongside the iPhone 3G, it hosted a relatively modest 500 apps.
In contrast, Microsoft was touting more than 18,000 applications for its Windows Mobile operating system, The New York Times noted at the time, while Palm was claiming 30,000 active software developers working on apps for its devices.
But after a few teething troubles (remember I am Rich?), Apple's App Store rapidly outpaced its rivals: 10 million downloads over the first weekend, followed by 100 million downloads in the first three months, and within a year that number had hit 1.5 billion across 65,000 apps.
"It is going to be very hard for others to catch up," Apple CEO Steve Jobs predicted at the time. The era of smartphone apps had truly begun.
By June last year 75 billion apps had been downloaded from Apple's store, and earlier this month the company revealed it now hosts 1.4 million apps which are available across 155 countries. In the first week of January alone iOS fans spent $500m on apps and in-app purchases (see the bottom of this story for a fuller history of Apple's App Store growth over the last seven years).
Reasons for success
There are some obvious reasons for Apple's success. Quality control is one: by keeping a tight rein on both the smartphone hardware and the operating system, and vetting the apps before they are allowed into the store, Apple could create a roster of high-quality, well integrated apps.
For developers, access to the iPhone's premium audience is extremely attractive, especially as Apple isn't much interested in making much money off the apps, unlike mobile operators who had been the gatekeepers, deciding how apps were distributed and sold at that point.
"This is the best deal going to distribute applications to mobile platforms," Jobs said when he unveiled the App Store. Developers keep 70 percent of the sales of their apps through the App Store, Apple keeps the other 30 percent. That might sound like a hefty slice, but developers don't have to pay credit card fees or for hosting, which is covered by Apple.
Apple has paid out $25bn to developers over the last six and a half years. That means Apple's cut is somewhere around $10bn - a significant sum but tiny compared to what Apple makes from selling mobile phones: the company reported revenue of nearly $24bn from iPhone sales in its last financial quarter alone. However, the limited revenue that Apple generates from the App Store doesn't imply that it's irrelevant - rather, analysts argue the App Store and the apps inside are an essential element of Apple's offering.
"Apple makes margin mostly by selling hardware, but apps are really what creates the loyalty to the ecosystem, be it from a consumer standpoint or for developers," said Thomas Husson, principal analyst at Forrester. "To me [apps] are the glue that sticks the whole ecosystem together because they offer brands and developers a direct opportunity to connect with their customers."
Apple was the first to make a commerical success of smartphone apps and Jobs was right to predict it would be hard for rivals to catch up. None of the rivals which were around when the Apple App Store launched managed it, even when they matched Apple's deal for developers, as iOS had already generated the necessary critical mass.
It took a new challenger in the form of Android to finally provide a genuine rival.
Apple has been surprisingly open with data about its App Store, and the data it shares helps us to understand the sorts of stories it wants to tell. At first the narrative was about the number of apps and downloads as it wooed consumers: now the emphasis is on developers and how much they make from working with Apple as it tries to prevent any defecting to archrival Android - which has, in a number of ways, already overtaken Apple on apps.
According to app analytics company App Annie, in the third quarter of last year Apple's App Store's revenue was around 60 percent higher than Google Play's.
But Google Play's worldwide downloads were 60 percent higher than iOS App Store downloads - and much of that growth is coming in emerging markets (this doesn't take into account the variety of other Android app stores that exist).
Apple leads on revenue because it still holds onto the premium market: richer consumers who can afford iPhones and are willing to pay out for apps or in-app purchases. Android has a vast consumer base but one that stretches from cheap smartphones up to high-end devices.
That's not all - according to data from AppFigures, Google Play has now overtaken Apple's App Store in terms of the number of apps it hosts, and also the number of developers working on the platform.
None of this of course takes into account the quality of the apps inside those app stores: Android is often criticised for the poorer quality of its apps. But it shows that Apple no longer commands the app world.
If it was previously the case that developers would build for Apple first, that's not always the case now. All of this will have implications for how the app store economy evolves over the next few years.
Often which operating system programmers choose to develop for first will depend on who they want to use the app, although as Dipesh Mukerji, senior director of product strategy at app maker Kony, points out: "Almost all of them have a plan to build for both. Those two operating systems [iOS and Android] rule the world and everything else is a distant third right now."
Daniel Rosewarne is CTO at Journl, a personal organisation tool, and said his company's decision to build an iOS app first and then build for Android was mostly down to customer demand.
But he said that building for iOS is also easier. "We found the early stages of getting up and running with iOS was just that little bit simpler. The common criticism of Android, which is the fragmentation of the platform, was a contributing factor in our decision. For iOS we knew the subset of half a dozen devices we'd be building for as opposed to the very wide range of different screen sizes and device types and so on."
Developing for Android and iOS isn't just about the underlying code: the user interface is very different and can cause problems for the unwary as well.
"The way in which you navigate is completely different. There's a very real opportunity for us to trip up in front of a broad Android audience [by] giving them and iOS specific user experience," said Rosewarne.
Emerging markets at the forefront
In the US and Europe developers still tend to build for iOS first as this is where the market momentum is. In emerging markets they are more likely to build for Android first. That also means developers will look at different ways of making money in future.
Marcos Sanchez, vice president at App Annie, said the growth of smartphone usage particularly in emerging markets will have a significant impact on the app economy. "It really does mean that emerging markets are playing a much more significant role and they have different requirements and they will dictate how things roll out and how developers will think about how and where they make their money."
"If you are developing for a market like India, pricing and how you monitise is likely to be extremely different to, say, Japan," he said.
In the short to medium term growth in emerging markets is likely to favour Android because the handsets tend to be more affordable. That means that as the Android install base continues to grow, it may start to narrow the app revenue gap with iOS. Already it is closing in on revenues that come from advertising on smartphones.
This is a potentially significant threat to the iOS ecosystem because one element of the Apple's appeal is that it gets the best apps and gets them first. If that's no longer the case because developers are choosing to develop for Android first instead, that takes away one of the reasons why you'd choose iOS over Android in the first place.
However, in such a dynamic market, it's hard to predict very far ahead: Apple is now selling more iPhones in China than in the US, which suggests it's very aware of how the market is evolving. Even tweaks such as the larger screen on the iPhone 6 Plus may be enough to intrigue and energise developers again and boost iOS.
There's also one other new technology development that may affect the apps market: wearables. This could shift the war of the ecosystems to a new, if somewhat diminutive, battlefield.
Android Wear devices have been on sale for some time now, while the Apple Watch will be released shortly. These are companion devices rather than standalone ones, so can potentially offer a big boost to either ecosystem, at least if they take off in any significant way (which is so far less than certain). But certainly many developers are already tweaking their apps to make use of the additional screen offered by smartwatches.
The app ecosystem isn't the only thing that consumers and businesses consider when buying a smartphone: the quality of hardware plus more prosaic calculations like price and mobile operators' coverage weigh heavily too. But as hardware innovation slows, how these player tweak their app ecosystems could become more important.
As Forrester's Husson notes: "The war is still on. It's not game over and things could change for sure."
A brief history of Apple's App Store
July 2008: Apple's App Store opens for business with 500 apps alongside the iPhone 3G. There are 10m downloads in first weekend and the number of apps available hits 800.
September 2008: App Store downloads hit 100 million on 3,000 apps. One developer says he has made $8,000 in a month.
April 2009: Apple announces downloads have hit the one billion milestone, with 35,000 apps available and the store open in 77 countries
July 2009. App Store downloads hit 1.5 billion. There are now 65,000 apps and 100,000 developers in the iPhone developer programme. "It is going to be very hard for others to catch up," says Apple CEO Steve Jobs.
September 2009: The two billion downloads mark is reached. Apple says the store features 85,000 apps from 125,000 registered developers. Jobs says: "The App Store has reinvented what you can do with a mobile handheld device, and our users are clearly loving it."
November 2009: Apple announces there are 100,000 apps in the App Store.
January 2010: Three billion downloads milestone reached. "This is like nothing we've ever seen before," said Steve Jobs. "We see no signs of the competition catching up anytime soon."
September 2010. Apple says there have been 6.5 billion downloads of 250,000 apps. It published its App Store Review Guidelines, and notes with its usual modesty: "The App Store is perhaps the most important milestone in the history of mobile software."
January 2011: Apple says there have been 10 billion downloads of 350,000 apps (including 60,000 native iPad apps). The store sells in 90 countries.
July 2011. 15 billion downloads are available in the App Store across 425,000 apps (including 100,000 native iPad apps). Apple says $2.5bn has been paid out to developers.
March 2012. Downloads hit 25 billion across 550,000 apps (170,000 native iPad apps) with the store available in 123 countries. Apple says $4bn has been paid out to developers.
January 2013: App downloads hit 40 billion (20 billion downloads in 2012 alone). Apple says there are 500 million active App Store accounts. It now features 775,000 apps (300,000 native iPad apps) which have generated $7bn in revenue to developers. The store is open in 155 countries. Temple Run was downloaded more than 75 million times in 12 months, freemium titles DragonVale and Clash of Clans generated over $100m.
May 2013: App Store reaches the 50 billion apps mark with iOS fans downloading 800 apps per second - 2 billion per month. Apple says $9bn has been paid out to developers, with 850,000 apps (350,000 native iPad apps) in the store.
June 2014: Apple says there have been 75 billion downloads of 1.2 million apps, and reveals the App Store gets 300 million visits per week
January 2015: Developers have now earned $25bn from apps in the App Store - $10bn in 2014, with $500m spent on apps in January alone. Apple says there are now 1.4 million apps (725,000 native iPad apps) in the App Store.