In an article covering the Palm Pre mobile device, Ars Technica makes a very important point about how devices utilize network connectivity, and what the assumptions are underlying their models of data storage and access:
Users just make changes to their data (contacts, calendar, mail, etc.), and Palm’s webOS handles committing those changes to whatever canonical data source it is accessing in the cloud. And herein lies the most important difference between the webOS and Apple’s iPhone OS: the iPhone was originally designed under the assumption that the canonical source of a user’s data (contacts, calendar, music, tasks, etc.) is a Mac. Palm’s webOS, in contrast, presumes that cloud-based services are the canonical source for your data (with the possible exception of media, which we don’t know about yet) …
Palm’s webOS does not presume any sort of tether at all. The company has totally ditched the idea that you will use this phone in conjunction with a specific “main PC” that contains the canonical, authoritative repository of your data. Instead, webOS draws seamlessly on a variety of data services–not data repositories, but cloud-based services that actively feed the device both data and critical context.
This is a deep, fundamental break with both the iPhone and previous, repository-based smartphone usage models, and it’s important enough that other smartphones are bound to follow.