Microsoft abandoned the "My" prefix in Vista for Documents, Pictures, etc. in the UI.
And then they brought it back in 7. I guess people complained.
I agree that omitting the "My" or "Your" where possible is the right way to go. If the overall context of the web page or application doesn't make it clear whose items are in question, adding "My" isn't always going to help much, or at all.
Consider Facebook, for example. Look at a friend's page. It probably has a "Photos" link. Would "My Photos" be clearer? Would "My Photos" refer to photos belonging to the logged-in user or photos belonging to the person depicted above the link?
It's the context in which the "Photos" link appears that makes its purpose and meaning clear, and that is usually the case.
Actually, it took me a while to figure out why "Photos" didn't take my to My photos, but to a photo stream of all of my friends. (Also, Win7 did not add the "My" prefix back to computer, documents, pictures, or anything.)
In fairness, there are aliases of some kind set up such that "John\Documents" and "John\My Documents" are synonyms. But the GUI very much puts "My" front and center for me.
Speaking of context, though, I've also heard "don't use My" as a recommendation for mobile UIs, because they don't have that much space to spend on the word to begin with...
This option makes tab completions much faster when you are working in the command line. Maybe I just don't pay much attention, but I don't think I've ever seen "My <whatever>" on a Linux system.
I'm really shocked about the differing opinions on this. I have always thought that the "my X" label triggers selfishness and suspicion in users, putting their guard up. I prefer "Your X" so that people feel like a team has been formed. They trust you with their data because they are entering information into your site. We're a team.
I guess it is understandable that you might not have yet gained the user's trust but I feel like then they wouldn't be your user.
Qualification: This is based upon my personal experience and opinion but not on extensive work experience producing publicly published copy.
For many people, it's going to feel/be more natural to write in the second person. Writing in the first person, when you are instructing someone else rather than describing yourself, takes more conscious effort. It's easy to forget and slip tenses. Also, and important, the resulting language/copy often ends up reading "stilted" -- it doesn't seem natural.
Unless you have a particular impression in mind, and the skill to pull it off well, I'd consider going with second person. It will probably be quicker to write, and if you really need to switch to first person, you'll have pre-existing copy from which to start.
P.S. I also tend to favor leaving such qualifiers off of labels, except when they clearly help distinguish an item.
"My Computer" et al. sounded patronising and childlike when it started and continues to do so now.
How about just "Items" and "Photos"? Unless there is something marked "Someone else's items" and "Someone else's photos", is it necessary to specify that they belong to the user?
I noticed that Google uses +You in English (as a plug for Google+ if you're not logged in) and +Ich (= +I) in German. Maybe they really just want a three letter word.
In Google Scholar, though, the link to your own Scholar page (if you've set one up and are logged in) is "My Citations" in English, so they seem to be using it inconsistently between products.
If it's inherently private data, use first person. For shared/public stuff, use second person. 'Your passwords' sounds too much like someone else is talking about my confidential data.
If you're talking about labeling things that belong to the user, and your site or app is supposed to feel like the site or app itself belongs to the user (their space), go with what the user would label them. For photos, what would the user write on a shoebox of their own prints? Most likely “My Photos”, but they also could just “Photos” if nobody else's things are stored anywhere nearby.
If the app or site does not belong to the user, but is clearly a third party the user gives things to in order to process them or perform some action on or with them, label it as a service person would speak to the user. How would the service person at Costco refer to those same prints? Probably “Your Photos” in contrast with "Everyone's Photos". In this case, the label "Photos" would be most likely to apply to all photos, not just the user's own.
Going with conversational style, keeping in mind who is the speaker for a given action, goes a long way to clarifying which stories need which terms.
This gets more complicated in "the cloud" but the same distinction (ownership vs operation, and who is the speaker for an action) can apply.
This is a classic example of a question that can only really be answered with data. Generic studies are good, but nothing beats data you gather about your particular UI.
Never use second person for UI, it's alienating because it subconsciously tells people that they aren't a part of the group and they don't belong. Studies show that conversion rates are much lower when you talk to people in second person for this reason.
I've actually been having a similar internal debate with an app I'm working on now, although for me it's between "My Whatever" and just "Whatever." Currently leaning towards "My."
"Your Whatever" isn't even an option though... don't like it at all.
I agree with gerad, use "My" -- it's shorter, cleaner, and appeals to the user more. "Your" creates distance between the app and the user, if one were all alone, "My" would still exist, but "Your" would not.