Mike Morton wrote a post that discuss the tenets to give some insights into how Microsoft’re creating “Office Web Apps” – lightweight, web-based versions of Word, Excel, PowerPoint, and OneNote. These tenets reflect the fundamentals that we aim to achieve and should provide insight into the tradeoffs we make.
-Users should trust that their document content will be safe during editing.
-Users should expect the familiarity of the Office user experience.
-Users should expect their documents to be displayed with high fidelity.