App - seldom has such a small word had such a big impact. It's always on the lips of tech's biggest and brightest firms: Apple, Microsoft, Google and BlackBerry. Smartphones, tablets, TVs, fridges, cars: if your devices don't already sport the ability to run small, slick, one-trick programs, then the option is only an upgrade away.
The term has become so ubiquitous that the American Dialect Society - a learned group dedicated to the study of the English Language in America - dubbed 'app' its 2010 Word of the Year.
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Instead of software suites - equivalent to a massive CD boxset aiming to cover everything and everyone - apps are more akin to singles. They're bite-sized, one-purpose applications, built for a specific function.
And mirroring what Apple did to the music industry, breaking the market into pieces and giving people somewhere to shop for the bits, Apple broke software into its component parts too, creating an App Store to provide users with a quick-fix solution to almost any problem.
An Apple a day
You might think that, with apps individually being more focused than traditional applications, you'd end up with a more coherent system, but the reality is more complicated.
Due to the typically isolated nature of an app, the notion of system-wide coherence is becoming deprecated in the app age. Logic Colony software developer Krishna Kotecha reckons this distinction between applications and more tightly focused apps will become "increasingly pronounced", although the focus and simple interfaces of apps will let typical users "get the most out of their software".
Certainly, usability has been key from the start with Apple's app model. Walsh argues that Apple "saved the mobile software ecosystem from itself", and says that before the App Store, it was incredibly difficult to sell apps.
The App Store deals with payment and distribution, along with making apps more discoverable. As iOS developer Jedrzej Jakubowski enthuses, "Customers are trained and encouraged to buy apps on a regular basis, which they can do in a very simple fashion."
Kotecha adds that even the much-criticised review process and 'walled garden' aren't a problem. "Unless you want to play fast and loose with platform development rules, private APIs, or user privacy. Apple has done a good job protecting the value of the iOS app ecosystem for both users and developers, because users don't experience the problems that break their PCs, such as malware and spyware. Users aren't afraid of buying and installing apps, and that's a really powerful thing."
Despite coming from the more open Mac development environment, Thomson agrees, and adds that the walled-garden criticism is overplayed: "Apple has found a good middle ground between the PC and games console approaches to software distribution. We can put apps in front of a broad consumer audience, and while there are restrictions, there aren't as many as if you wanted to write for, say, a Nintendo handheld."
A bad Apple
Aside from the well-publicised review process, the App Store has some shortcomings that impact on existing products, but these also point to how Apple may improve its offering in the future.
Thomson would like to see more flexibility in pricing, with the ability to offer upgrades - a common source of friction with users - although he concedes that this this is "perhaps a sign of old-school thinking, given that Apple now rarely offers upgrade pricing on its own products".
Elsewhere, although the app-buying process is discoverable, apps themselves are trickier to unearth due to the sheer number available and Apple's relatively limited search functionality; Thomson notes that many people rely heavily on the charts to 'discover' apps, often keeping a very limited number of products selling well and condemning the remainder.
There's also a tendency for app prices - especially for games - to 'race to the bottom', which has trained users to expect apps to cost 99 cents, or 59p. These needn't be considered entirely bad things.
As developer Neil Inglis points out, "from a consumer standpoint, the two big things are cheap apps and an almost endless supply of apps - I can't remember the last time I looked for an app to perform a task and couldn't find something".
However, because of the difficulty in recouping development costs, there's a tendency for many apps to be very simple, hastening the atomisation of software. This direction means things are going to be tough for any app that's not marketable to a widely understood niche, relegating general or experimental apps to relative obscurity.
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But atomisation can be a benefit to developers and users alike, assuming an app has a real use. As Kotecha explains, "It keeps apps focused tightly on one thing, and focused apps aren't a bad thing at all, because most non-technical users barely use a fraction of the functionality available on their desktop applications."