The "smartphone war" until now has revolved around selling smartphones to non-smartphone users, with three clear winners. Apple is winning the 'business' game, selling high end, high margin handsets, taking the majority of the profits in the market by selling high-end devices, based largely on the user experience. Google is winning the 'market share' game, getting the majority of devices running smartphone operating systems into the pockets of smartphone. But Google isn't selling Android phones – they are giving away the software to those who are. And out of those hardware manufacturers, Samsung is clearly winning the game of making money from selling lots of devices.

But now that smartphones are owned by the majority of the market (at least in most developed countries), the next stage of the battle will be selling smartphones to smartphone users — poaching their competitors' customers by offering them something their current handset doesn't. My guess is that this is where the game will change from simply offering smartphone features to offering the best smartphone features.

Which raises an interesting question.

What are "Smartphone features"?

A few years ago, I kept seeing the same problem at work; trying to understand the size and rate of growth of the smartphone market meant watching a number of different research sources. Industry analysts tracking technology sales, media analysts tracking device ownership, web analysts tracking internet usage, and so on.

I'm reasonably used to tracking different people using different techniques and/or different metrics and trying to piece together a bigger jigsaw out of all of them. But for smartphones, something else was missing; a consistent definition of what a 'smartphone' is. Some went with a UI-flavoured definition, such as a phone with either a full QWERTY keyboard or a touch screen (as opposed to a simple numeric keypad, which meant that Symbian devices like the Nokia N95 weren't included.)

Others went with a more software/systems based definition, such as the ability to install 3rd party applications (which meant that the original iPhone wasn't included until the second version of the OS was released – along with the App Store.) Others still based it on next-generation (at the time) wireless technology like 3G and WiFi.

In one sense, this problem has pretty much gone away; the fuzziness around what defines a 'smartphone' has disappeared thanks to the evolution of smartphone platforms. As a result of the impact of the iPhone, it is now the oldest of all of the smartphone platforms; Windows Mobile has been completely rebuilt as Windows Phone, BlackBerry 10 is an entirely new platform, and Symbian has pretty much died. So the problem of how to categorise phones has gone away — now they all have more or less the same kind of functionality.

But the question remains – what is it that makes a smartphone "Smart"?

I suspect that most people's first answer would be 'internet'. Well, there are plenty of 'feature phones' (aka. Dumbphones) that can still pull up a page from the web or connect to email accounts. I think a phone can have a web browser and still not be a 'smartphone'.

3rd party applications? Well, I'm not sure if I would go with a definition that would rule out the original iPhone (and again, there are applications available for phones that I wouldn't call 'smart'.) But this feels a bit closer to a real point of differentiation.

But I think the important point is perhaps a little less obvious;

From the Wikipedia page about Smartphones;

One of the most significant differences is that the advanced application programming interfaces (APIs) on smartphones for running third-party applications can allow those applications to have better integration with the phone's OS and hardware than is typical with feature phones.

Some examples of this would be the ability to have a Maps application look up the address of someone in your Contacts list, a birthdate for a Contact showing up as a birthday in your Calendar, a social network app being able to pull photos from your phone's Camera, a game app being able to play music from your MP3 library and so on.

To me, this is a feature of smartphones that has been under-served by the current 3d party application and accessories makers. Perhaps I'm saying this because I'm mainly an iPhone user; one of the things I like about Android (although haven't really played around with enough) is the 'open', modular design; the idea that if I don't like the Mail application, or the home screen, or the keyboard – well, I can just swap it out for another one. It means that apps can talk to each other in a way that iPhone apps just aren't allowed to.

Multiple apps on multiple devices

It's already clear that the days of one person using one computer are over; according to Google, we currently use an average of 2.9 internet-connected devices — and that number is rising. So an application that lives entirely on one device is obviously going to be less useful than one which lives on several. (For example, if you keep your notes in the Apple Notes app, then you are limited by what you can do with them on a PC.)

But as well as working with different devices, there is an increasing need for applications to work together on the same device. In other words, the lines between devices, platforms and applications are blurring.

Andy Ihnatko's recent reports on why he switched from iPhone to Android touches on an interesting issue;

Getting stuff done with a phone is muchly about moving information between multiple apps. That characteristic is peculiar to phones. Most of the things I do with my phone involve using one app to obtain a scrap of data, and then pushing it into another app to work on it a bit, and then sending or sharing it using a third app.

A couple examples of how the ability to do this on iOS extends beyond copying and pasting;

Drafts - iOS txt editor app that lets you send data ("drafts") to a huge number of other apps - whether that is sending it as a tweet, a Facebook post, an email, an item in a To-Do app, a file on Dropbox etc. etc.

TextExpander - originally a Mac application, now also an iOS app that other apps can pull functionality from.

But this is an area where Android has an edge; because of the 'open' design of the system, it has been built to let applications take a more fundamental role in the workings of the phone. Want a different kind of keyboard, or a contacts application, or a totally different home screen? Android is built to allow that kind of customisation (by users, or networks, or handset manufacturers.) iOS devices are designed to give you 'the best' by default — assuming that what Apple think is best is actually best for you. (The idea of opinionated design is that it doesn't aim to be all things to all people — if it isn't for you, then it isn't for you.) But by focussing on a particular opinion means that if it is for you, then it aims to be the best for you.

But thats all fine for apps. What about accessories?

Right now, the phone accessories you own are probably fairly cheap; a pair of headphones, a Bluetooth headset, a charger (or a few.) But smartphone accessories are getting smarter — maybe you have an Apple TV or Airport Express, which lets you stream music or video wirelessly to a stereo or TV. (Or maybe an app that connects your phone to your TV set top box.) Functionality gets smarter, so devices get more expensive.

Perhaps you've been burned when Apple swapped out the old Dock connector for the new Lightning port, and your phone no longer plugs nicely into your speakers. But thats probably still something that costs less than a brand new £650+ phone.

Now, what happens when your accessories cost more than the phone? Say, you get a car that has features that only connect to iPhones (like a stereo that connects buttons on the steering wheel to iPod controls, or the eyes-free Siri integration), or a Samsung TV/stereo that only connects to a Samsung phone? (Or the internet fridges that seem to forever be just a couple of years away…)

What happens when smartphone apps start connecting to systems in the home — your lights, or your central heating? Currently, it looks like the people buying the latest iPhones are also the people with the most disposable income, so also able to spend the most on things like cars, stereos, fancy TVs etc. If you are making these high-end items, you probably need to consider iPhone integration before Android, BlackBerry, Windows Phone etc. Which then has obvious implications for the next generation of Smartphone owners, and how other platforms need to think outside of the Hardware/OS/Apps world if they want to poach Apple's most valuable customers.

For users, I think the issue is thinking more carefully about what you want from a smarpthone (or tablet) platform, rather than just the devices. 5 years ago, the issue was about the device and the software it came with. When the App Store exploded, the availability of 3rd party apps became important. I think the next step is going to be about how those apps work with one another - whether that is on the same device, or on something else.

Today, this is the kind of issue that 'power users' (read: nerds) care about. But its only a few short years ago that it was only 'power users' who cared about websites and apps on mobile phones. Now its pretty much everybody.