For me, one of the most powerful UX pivot points that Cloud offers designers is to build optimized and contextual solutions, reflecting how users' roles, tasks, goals, environments, and devices--their context of use, if you like--can vary.
Think about how you might use LinkedIn, for example. A power update to your LinkedIn profile such as adding abstracts for latest publications or completing your profile might be done on your PC using the LinkedIn website. Browsing through your contacts, groups or news features might be done with swipe gestures on the LinkedIn app on your tablet. Accepting a LinkedIn invitation to connect via email can be done on your smart phone with a few taps and you can see updates at a glance too.
We just don’t have to think about these different usage scenarios devices. We just do it because the interactions have been understood and designed for. We know they all rotate around our profile as the source of truth. We just perform the different tasks on different devices intuitively, as the context demands. That's the whole point of a great UX, I guess, commonsense ways of ensuring users don't have to think! Same principle applies to enterprise applications, really.
For developers, this offers great opportunities too to enable great UX from the Cloud by relying on APIs and service oriented architecture. By writing UI services and leveraging design guidance such as UX design patterns and guidelines and not sweating about writing new UIs from scratch for every device, developers and partners can spend more time on issues such as security, performance, integration, scalability, speed, all the stuff that's critical to business while anticipating changes in UX that will come for sure. For customers, such cloud-based enablement means continued ROIs by using existing data while extending the UX of existing apps and providing new experiences too to make users even more productive.