The HTC HD2 was released in November 2009, running Windows Mobile 6.5 Professional. The device brought along several new features to the smartphone world such as a faster processor and much larger display. After the release of the HD2, and due to its success, smartphones of the day started evolving into phones with much larger displays and faster processors.
Latest hardware is important in the eyes of the consumer
Analysts were initially skeptical regarding the extremely modern hardware. They did not think that consumers could justify paying a premium for a device with a faster processor and that the improvements would not be that noteworthy. Along with that they felt that bringing a capacitive display would be useless as Windows Mobile needed a stylus to function satisfactorily.
However HTC debunked their theories by adding a version of HTC Sense over the default UI so that thumb operation improved drastically. Along with that the newer processor was able to carry out multiple tasks very efficiently and became one of the main selling points of the device. As some applications still needed a stylus to be used comfortably, HTC started selling a first-party stylus as well.
Large display size
People initially believed that the 4.3 inch display would hinder the portability of the device by quite a margin. As it was the first phone with such a display, people did not have any prior experience with smartphones of its size. When the phone was released, some people did indeed find the size to be too big, while some others thought it was a worthy trade-off for the larger display.
However with the immense sales of the device, it became clear that people did not find the size to be that big of a problem to deter them from buying the phone. This led to the creation of several new smartphones with 4.3 inch displays such as the Motorola Droid X and the HTC Desire HD.
How it influenced future smartphones
The HTC HD2 influenced the future smartphones in a number of ways. It brought along faster processors and larger displays to the smartphone world which was a trend that has caught on with the public. Along with that it also showed that UI customizations can improve the overall experience of a smartphone considerably and companies should invest time and resources in it. As a result other companies have come out with their own skins such as Sony Ericsson with its UX skin for Android for improving the device usability.