i could go on endlessly ... these examples are impossible with a desktop,I use just all of these apart from Twitter. They are certainly convenient but no one could describe them as a rewarding visual experience.
The problem is that we are all being channeled (or forced) down this road by the market that is driving people to mobile devices, which are incapable of providing the full experience.
Your own example is a good one. How can anyone buy anything other than a name brand with which they are familiar using a mobile phone? When you think about it this may be the only think that can save PCs?