The smartphone market ain't what it used to be. Four years ago, Symbian ruled the world—it was totally dominant in every market but three: Japan and China both had strong showings from Linux, and the North American market was split roughly evenly between RIM, Microsoft, and PalmSource. Worldwide, smartphone sales amounted to some 60 to 65 million.

Then Apple came along with the iPhone in 2007 and changed the world.

The iPhone did four things. It showed us what could be done with finger-based user interfaces—that they could be easy to use, easy to type on, flexible, and good-looking. It made smartphones mass-market, consumer-oriented gadgets, breaking them free of their corporate shackles. It showed that smartphones were viable web browsing platforms, just as long as they were equipped with a good browser. And, eventually, it showed that there was a lot of value to be had in integrating an online application store.

Windows Mobile was a solid performer in the old smartphone world, but it never moved into the new, post-iPhone smartphone world. Windows Mobile 6.5, released in May 2009, was a half-hearted attempt to bring the system up-to-date with a finger-friendly home screen and Start menu-type-thing, but the interface was crudely grafted on and plainly unsatisfactory. This wasn't finger-friendly, consumer-friendly, modern smartphone software, and everyone knew it. It didn't halt Windows Mobile's marketshare slide, much less turn it around.

If Microsoft wanted to remain a player in the smartphone market, something would have to change. Windows Phone 7 is that change.

Windows Phone 7 is a smartphone platform that's aimed first and foremost at consumers. It's designed from the ground up for a finger-driven interface. It's built to be clean, attractive, and consistent. The ambition is that it will finally give Microsoft a platform that will enable it to take on the iPhone and Android phones. Virtually everything that Windows Mobile did is now ancient history. Windows Phone 7 ushers in a new era of Microsoft-powered smartphones.

Hardware

In many ways the hardware is the biggest similarity between Windows Mobile and Windows Phone, because with the new operating system, just as with the old one, Microsoft is leaving the hardware to third parties. Unlike with Windows Mobile, however, the company is being extremely strict about what's allowed and what's not. Every Windows Phone 7 device must meet the minimum specification.

Processor 1 GHz Qualcomm Snapdragon GPU Qualcomm Adreno 200 RAM 256 MB Flash storage 8 GB Screen resolution 800 × 480 (exactly) Touch Capacitive multitouch with at least four contact points Cellular connectivity GSM/GPRS/EDGE/UMTS/HSPA (HSPA+ optional) Wireless 802.11b/g (802.11n optional), Bluetooth 2.1 + EDR, FM radio Hardware buttons Start, search, back, volume, power, and camera (with half-press focus) Camera 5 MP, dedicated flash Sensors A-GPS, accelerometer, compass, proximity, light Ports Micro-USB, 3.5mm TRS headphone jack Miscellaneous options Hardware keyboard, user-accessible microSD slots

This is a high specification; these are premium handsets, so they'll be priced towards the upper end of the spectrum. When Windows Phone 7 was first announced, Microsoft said that at some point after launch, lower resolution 480×320 devices would also be supported, and even further into the future, an as-yet unspecified third resolution/form-factor would also be added.

At the moment, however, all the focus is on the 800×480 models, and personally, I think Microsoft should stick with this for as long as possible before venturing into new designs. The iPhone has demonstrated that you don't need a billion different models to be successful, and by sticking with one resolution, the job for application developers is made a great deal easier.

Even within these constraints, the initial handset partners—Dell, HTC, Samsung, and LG—have a reasonably broad range of options, with screens ranging from 3.5" to 4.3", 8 or 16GB of storage, and one with an 8MP camera. Dell's phone, the Venue Pro, includes a vertical (potrait) slider keyboard, and next year Sprint will release an HTC device, the 7 Pro, which will include a more conventional horizontal (landscape) slider keyboard. We took a quick look at the launch models last week, and you can see our initial thoughts on the UK and US offerings.

Some models appear also to have forward-facing cameras. Windows Phone 7 doesn't presently support video calling, which is unfortunate for those of us in parts of the world where such things have been a feature of the telephony landscape for many years. If this is indeed the case, it may be an indication that video calling is coming sooner rather than later.

The most unique, Windows Phone 7-specific feature of the hardware is the hardware buttons. Although the user interface is predominantly touch-driven, the specification mandates a set of hardware buttons. The power, volume, and camera buttons are self-explanatory; it's the Start, search, and back buttons that will be the hallmark of Windows Phone 7 devices. These mandatory buttons are perhaps the biggest reason why, to the chagrin of many, devices that otherwise ought to live up to the Windows Phone 7 specification such as the HTC HD2, won't be upgradable, and will be lumbered with Windows Mobile 6.5 for the rest of their lives.

The button placement is also defined by Microsoft. The back, Start, and search buttons must be on the front of the phone and in that order (though they can be mechanical or capacitive, or some combination of the two). The volume rocker switch must be on the top of the left-hand side, the power button on the top of the right-hand side, and the camera button on the bottom of the right-hand side.

The 3.5mm headphone jack must also support three buttons, volume up, volume down, and a third to answer calls/initiate voice dialling.

Notably missing from the feature list is support for CDMA and EVDO. CDMA support will arrive next year; at the moment, Windows Phone 7 handsets are GSM-only.

The specification allows for minor variations, but it doesn't allow for any radical deviations. The result is that the handsets are far more similar than they are different, and unless Microsoft substantially liberalizes the rules, it looks like it will be difficult for OEMs to produce any truly exceptional or unusual devices. This is good for application developers, as they have fewer targets to aim for, and it's arguably good for consumers, as it means that they can buy a Windows Phone 7 phone with confidence—if you know your way around one Windows Phone 7 phone, you know your way around them all.

It may, however, be bad for the OEMs, who may find themselves with little ability to differentiate and distinguish themselves from each other. OEMs are allowed to include custom applications, but their ability to stamp their own branding onto phones will be far weaker than it is with Android and was with Windows Mobile. If Windows Phone 7 is anything short of an enormous success, it's easy to see them giving up on the platform.

The model I have is a Samsung Omnia 7, and I'm using Orange, in the UK. The most striking feature of the Omnia 7 is its screen; it's a frankly beautiful 4" Super AMOLED display, whose vibrancy and viewing angles are quite delightful. The version I have has 8 GB of internal storage, though a 16 GB version should also be available.