Last month saw the fourth birthday of Apple's iOS App Store, which has been selling apps and games to iPad, iPhone and iPod touch owners since 10 July 2008. It's been one of Apple's most successful innovations of the 21st century, so we've decided - with some assistance from eWeek - to look back on the milestones, statistics and notable successes of the iOS App Store.

There's an app for that - and for 724,999 other things

The App Store has grown from a starting line-up of 500 apps to a massive line-up that's not far off the million mark: the last official count put it at 650,000 apps, but current estimates are around 725,000.

Google Play, the biggest rival service, is catching up (achieving faster growth thanks to its less exacting approval process, which amounts to a virus check and little else) but is still behind, containing about half a million apps in June.

Apple App Store

Global success

The App Store is now available in just under 200 countries across the globe, including the all-important Chinese market. The most recent additions were made at the end of June, and included Papua New Guinea, Federated States of Micronesia and the all-important Albanian market.

30 billion downloads, and other landmarks

The App Store saw its billionth download in 2009. A 13-year-old Apple fan named Connor Mulcahey was lucky enough to break the landmark, and was rewarded with a $10,000 gift card, a MacBook Pro, an iPod touch and a Time Capsule.

Since then the App Store has left that mark far behind. Apple ran a '10 billion app countdown' during the later days of January 2011, breaking the milestone with a download of Paper Glider by Gail Davis of Orpington on 22 January 2011 (at 10.26 am, apparently). A similar countdown started in March of this year, with the App Store passing the 25 billion download mark on 3 March 2012. The lucky downloader again collected an iTunes gift card worth $10,000, but it would appear the extra goodies weren't on offer this time around.

At WWDC Apple trumpeted that it has now passed 30 billion downloads, a truly phenomenal figure in anyone's book.

Tiny Wings

Ahead of the Mac

Some believe that iOS will eventually overtake OS X as Apple's premier operating system. It's certainly ahead on the app front, setting an example with the App Store that OS X followed in January 2011. The Mac App Store is accessible to desktops running Snow Leopard or a later version of OS X. Boo! Desktop computing!

What's in a name? Lots

Say the words App Store and most people would probably assume you meant Apple's iOS shop, unless they were Google fanboys or just trying to be difficult. But it's certainly not the only store for buying apps, and plenty of other companies have tried to call their offerings something similar.

Apple applied for a trademark on the term in 2008, but last year a judge refused to let the company apply an injunction against Amazon and its Appstore. That dispute continues.

Infinity Blade 2

Cash money

Virtually all apps sell for less than the price of a pint in central London - ha ha, so do most cars!!! - but the download figures are so high that they mount up quickly. At WWDC Apple stated that its App Store had paid out a cool $5bn to developers.

And what about the company's own slice? Piper Jaffray analyst Gene Munster estimates that Apple makes 18 cents from the average app download, giving it a net profit of $538m by last July. Removing the cost of storage and delivery, we get a formidable final figure of $292m.

Free: the best price of all

Apple has made plenty of cash from its App Store, but well over a third of the apps on there are actually free, attempting to recoup the costs of development through advertising, in-app purchases or driving traffic online.

eWeek points out: "In June 2010, 7 percent of app revenue came from in-app purchases within free apps, while 22 percent came from in-app purchases in paid apps. In June 2012, those figures evolved to 68 percent and 16 percent, respectively."

This is particularly true in the publishing business: a whopping 91 percent of the top 300 most popular free Newsstand applications feature in-app purchasing.

At the other end of the scale, the most expensive app we've managed to find is The Alchemist SMS, which caters to the needs of steelmakers and scrap metal recycling experts. It costs £699.99. If anyone's tried it out, let us know what you reckon in the comments box below.

The Alchemist SMS