Dustin Curtis on using “your” versus “my” in user interfaces:

After thinking about this stuff for a very long time, I’ve settled pretty firmly in the camp of thinking that interfaces should mimic social creatures, that they should have personalities, and that I should be communicating with the interface rather than the interface being an extension of myself. Tools have almost always been physical objects that are manipulated tactually. Interfaces are much more abstract, and much more intelligent; they far more closely resemble social interactions than physical tools.

The answer for me, then, is that you’re having a conversation with the interface. It’s “Your stuff.”
It’s funny how subjective this stuff is.
For me, I’m on the opposite side of the coin as Curtis. As he mentions in his post, because I think of my device as an extension of myself, “my” is the most appropriate modifier to use within applications and settings on my devices.
“Your” seems foreign.
Think about how invasive it feels when someone inadvertently grabs your phone at a party thinking it’s their’s and starts rummaging though it. “That’s my phone!” is the first thought in your head.
Dustin is wrong.
Is’s My Stuff.