Tablet computers are larger than a smart phone but interact with the user in much the same way, using a touchscreen as a primary input device.

Touchscreens have been pivotal to the recent success of smartphones, so it is no surprise that e-reader manufacturers are looking at ways to bring the technology to their devices.

The HTC EVO, with a height and width marginally bigger than a typical 3.5 inch screen phone, somehow fits a 4.3 inch screen on it.