The Mobile market is forever changing. Back in the 90's the clear leaders in the analog market was Motorola. Cell phones moved to digital and saw the rise of Nokia and Ericsson. Sony entered the game with their walkman and digital camera phones. Motorola reinvented itself and returned with the famous clam shaped mobile phone with dual batteries for extra standby. Samsung and LG then started some really affordable phones. They were stylish and offered everything else the other major companies had at a fraction of the cost. Good deals with telco companies also made sure they were pushed into the consumer market.
Smartphones started to come on the market running symbian operating systems. They were the first featured phone with apps and browsers that allowed basic online tasks like email and reading content. Blackberry because a force in the corporate world with its own dedicated email network service and secured phones. Apple decided to get in on the game and eveyone giggled when they first realesed the iphone. It dominated with the 3G and took a lead that would remain for a few years. Most of the traditional blackberry customers moved to Apple. Google saw mobile as a threat to their own existence so decided on developing andriod to compete with Apple.
Android was free and other companies jumped on the band wagon to try and get some market share back from Apple. Samsung released the S2 which was a worthy competitor to the iphone 4. Market share has balanced but more and more users are going with andriod because of the price of the handsets.