A smartphone is a mobile phone with enhanced multimedia capabilities that traditional feature phones lack.
There is no standard definition of the term 'smartphone' but there are a number of features that can be found on almost every device including an operating system, the ability to add applications, web browsing capability, and a digital camera.
Smartphones generally come in one of two form factors, with some such as the HTC Desire HD relying entirely on a touch-screen for input, while others such as the BlackBerry Torch have a physical keypad, but may also have a touch-screen.
Smartphone sales were up by over 70 per cent last year, and accounted for a fifth of the 1.6 billion mobile phones sold, according to Gartner.
At present the most popular smartphone operating system is Android, having overtaken Symbian in terms of sales in the last quarter of 2010. The BlackBerry, Apple's iOS and Windows platforms make up the top five.