Years ago there was a discussion on how web apps should address their users. Should the link to a user’s profile say Your profile or My profile? On the one hand, if the app is perceived as a tool — an extension of the user’s own faculties — then My profile fits the bill. On the other hand, if the app is seen as an interface to a service, then Your profile makes more sense.
Since the preferred nomenclature will differ between users, the best solution is probably to avoid the issue altogether. Just say Profile and move on down the backlog. Where this model really shines however, is in user experience design.
There will be parts of the experience that should belong to the user (as tools) and other parts that belong to the app (as the interface). Knowing the difference makes it clear when to be traditional and when to be bold. Critically, an interface should never make unexpected changes to otherwise intuitive tools.
Scrolling in a web browser is a good example. We expect it to work consistently across sites. It is a tool intrinsic to the browsing experience. So in cases where the interface changes how scrolling works our intuition goes out the window.
A more interesting example is a browser’s viewport. While it’s fine for an interface to respond to the viewport size, resizing the viewport itself is a tool of the user. And while web apps seldom change the window size they often come close by limiting the usable viewport through modals and fixed elements.