Not sure if this is really due to the lack of space on mobile devices or if there are a number of factors, but I have noticed that the 'organic' way of organisation and displaying content (think of the way you organise apps on iPhones or iPods) where users can stack together apps into groups seems to be a predominant strategy for mobile devices. Yet people seem to be more familiar with the tree/folder structure strategy for desktop applications.
I would have thought that the choice in the strategy used for organizing and displaying information should be largely driven by the content that needs to be displayed and the interactions involved rather than the type of device (although screen space is obviously a relevant factor). With many applications now being developed and deployed in the cloud, applications that are accessed through the browser should have very similar behaviour regardless of whether they are accessed on the mobile phone or on the desktop computer (or maybe this is an incorrect assumption?).
The question is, why do iPhones use the 'organic' way of displaying apps while the Windows phones use the 'structured' way of displaying apps, but for Apple or Windows desktop OS both use the classic tree/file menu structure of displaying content? Is this a legacy of traditional desktop application design, and will there be less of a distinction in the age of SaaS applications?