[TeMPOraL]

There are shades of grey in SaaS implementations, though. That the product is operated through a third-party server doesn't always imply it needs to be only available when you're on-line, and doesn't imply that your data needs to be taken hostage. A big part of the problem here is what 'stillkicking mentioned - doing away with files. Instead of data files, you have "documents" (meaning specific to a service). You can no longer open them independently, copy to local storage, or e-mail it to a friend - you're restricted to "sharing" them within the platform. This is not a technical necessity. It's just driven by business model.