This year has seen more than its fair share of novel and interesting smartphone models, particularly those with touch-based user interfaces. In fact, there is plenty of justification for regarding 2008 as the year that the smartphone came of age.

Smartphones have been around for longer than most people realise. Symbian, the company founded to develop a new operating system specifically for phones, celebrated its tenth anniversary this year. However, they have always represented a small fraction of the global handset market, with broader popularity always predicted as 'just around the corner'.

One device that has perhaps been more responsible than any other for popularising the smartphone has been Apple's iPhone. Although originally launched in 2007, this year ushered in an updated model with support for 3G networks, enabling users to make better use of Apple's desktop-class Safari web browser.

Apple's main innovation, however, has been the iPhone's touch-based interface that does away with most of the buttons found on a typical phone and instead uses on-screen controls activated by a fingertip.

The success of the iPhone saw many other vendors introduce phones with a touch-based user interface, with varying degrees of success. HTC introduced its first such handset in 2007, but continued to add to its line-up in 2008 with successively sleeker models such as the HTC Touch Diamond, launched in May.

HTC took the approach of adding a touch-based interface that sits on top of the Windows Mobile operating system. This has been copied by other vendors, such as Sa msung with its Omnia model, and to lesser extent by Sony Ericsson with its Xperia X1 that is mostly stylus-driven, but adds some gesture-based controls.

The iPhone's influence can also be seen in RIM's BlackBerry Storm, the first to do away with what had been a vital feature of the BlackBerry: a decent Qwerty keyboard for composing email messages.

RIM added its own innovation in the form of a screen that gives mechanical feedback when pressed, designed to make the on-screen keyboard feel more like that of a physical one, as well as providing reassurance to the user that they have activated an on-screen control.

This autumn also saw the first handset based on Google's Android platform in the shape of the T-Mobile G1. This has many of the features of a touch-based device, enabling users to control the device and reorganise the screen layout using fingertip control, but the display also slides aside to reveal a mini Qwerty keyboard for text entry. However, the G1 is a heavily web-focused device that possibly has more in common with mobile internet devices than most smartphones.

While touch-screen phones have been getting attention in the consumer end of the market, business users have also had new devices. RIM introduced the BlackBerry Bold, a new high-end Qwerty device with an updated user interface, aimed at professionals.

Nokia also introduced the E71, a device aimed at the same email-centric business base as BlackBerry users. The sleek and slim (10mm thick) handset has proved a hit with many professionals, thanks to its Qwerty keyboard and features such as the ability to lock the device by sending it a secret text message, and support for separate work and personal home screens.

Other business-focused handsets included HP's iPaq Data Messenger and Voice Messenger models, which were representative of a great many other handsets based on Windows Mobile 6.1, itself released earlier in the year.

This version of Microsoft's mobile platform added a number of enhancements aimed at business customers, the most significant of which is the ability for IT departments to control and manage handsets via Active Directory. It also added a new VPN client and various user interface enhancements.

This year also saw the shock announcement from Symbian that its smartphone platform is to be freely available in future under an open-source licence. As part of the move, Symbian itself has effectively been acquired by Nokia while management of the platform, the most widely deployed smartphone software globally, is to pass to a new body called the Symbian Foundation, which is expected to begin operations in 2009.

Also due in 2009, according to rumours, is the long-awaited new mobile platform from Palm. According to plans announced at the time, this will combine features of the current Palm OS with a Linux-based core, and a greater focus on web access.

With all of this happening, 2009 looks set to be just as eventful a year as 2008 has been for the world of smartphones.