In a new blog post, Microsoft goes over Office on Demand. With Office on Demand, users can run temporary instances of popular Office 2013 productivity suite apps such as Word, Excel, and PowerPoint. Using the Click-to-Run architecture, Microsoft was able to make this happen.
"What if you could use all the powerful features of the Office applications without doing an install at all? What if you could just use the applications on demand? Whatever Windows computer you were on, you could log in to a website, run Word, Excel, or PowerPoint, and when you were done, they’d go away. How could we make that happen?" Microsoft asks in an official blog post. Using whats called "user-mode streaming", Microsoft was able to create Office on Demand. Available to Office 2013 subscribers, Office on Demand allows temporary instances of Word, Excel, PowerPoint, Access, Publisher, Visio, and Project to run temporarily on computers where they normally would not be able to install software. Simply click on "My Office" tab on the Office 2013 Customer Preview site and "Create New" icons will start the Office on Demand apps. Once you close the app, they go away. Here is a quick overview of Office on Demand:
■ Office on Demand is a feature for subscribers of Office 2013.
■ Only the parts of the application you need are actually downloaded as you need them (not the whole thing). They run locally, and it’s very fast, only seconds depending on connection speed.
■ It’s always the latest version of the application.
■ Office does leave behind cache files for performance reasons, but the applications cannot be launched from shortcuts on the local computer. To use the applications again, always start from the website.
■ You have to be online to use it, and you have to be logged in to Office to validate your rights to use the software.
Source: Office Blog 
