Dustin Curtis:
A question that inevitably comes up very early in the process of designing a new app is this: should the interface refer to the user as “your” or “my” when talking about the user’s stuff, like in “my profile” or “your settings”? For a long time, this question ate at my soul. Which is right?
Interesting thoughts about the relationship the user has with the user interface.
As a rule, stay away from both "my" and "your" in navigational elements — this is often implied — and use "your" when the interface communicates with the user but only if needed for clarity.