(Yes I knew Dropbox had a website. I'm speaking for all those users who downloaded it once and now use it to synchronize their computers, never realizing there is a website too. And yes, these people do use the public folders: they right click & send the link to someone, but don't connect that to the idea they can see their own files on the web)
I had a very difficult time explaining to her that her same folders and files are available via the web interface.
Those people are out there.
I'm always espousing the necessity of backups to my friends/family, which means I've usually got the role of setting up a Dropbox account for someone without a technical background.
When I say that their "My Documents" folder is a level above their Dropbox folder, I get a blank stare. While many users can create folders and somewhat organize their data, to most non-experienced users I've encountered, the mental image of a hierarchy of data segmented into directories is not represented clearly enough by the GUI's of modern operating systems.
When people hear the word "folder" and see the folder icon, they don't think of it (the way we do) as a metaphysical representation of the overall directory tree. They simply think of a folder on a desk. A folder on a desk is not usually inside another folder. It's usually just sitting there. So a user without knowledge of the tree/hierarchy model just sees various sets of folders, not a set of folders within other folders. Therefore getting things into their Dropbox is an exercise of mental visualization that takes time and explanation.
Further, once I've somewhat explained this concept, I usually leave it there and tell them that "the green checkmark means you're backed up." The web interface is a whole new exercise in visualization that is quite a bit more difficult to pick up. Even after I tell people that "your data is synced to the web interface," they don't initially understand what that entails, and believe the web interface is separate from the files they've "backed up" on "their Dropbox" (the local Dropbox folder.)
My girlfriend (A/B test subject #1) is used to using the "upload" button on the Dropbox web interface because for a good while she didn't realize things on her local folder would sync to the web interface. She's also not entirely comfortable with the hierarchy model, and the "upload" model is in fact easier for her to understand.
Reminds me of the SJ quote from an AllthingsD conference where he says every usability test hits a wall when the user encounters the filesystem. I've seen this evidenced again and again.
You might get a blank stare, because Windows itself has been trying (somewhat unsuccessfully) to move away from this hierarchical model, blurring this metaphor. Consider the Libraries feature, which can essentially collect many folders (My Documents, Dropbox\Documents) and can represent them as a single virtual library.
Similarly, "Favorites" further serve to flatten this hierarchical model (Desktop, Downloads). And finally, consider things that look like folders but aren't physical folders at all (Recent Places).
I actually didn't understand your "level above" analogy either. On Windows 7, the My Documents is:
C:\Users\barik\Documents (appears as My Documents but the folder is actually called Documents, hah!)
and
C:\Users\barik\Dropbox
which is at the same level?
Perhaps also worth noting, in a clean Win7 install, the folder is initially labelled "Documents". It's not until you install a program that tries to access it by the "My Documents" link (there's actually a hidden link with that name) that the folder appears to rename itself to "My Documents".
My gawd, I can't even figure out what's where in the Libraries context.
You are obviously right. But people have been using hierarchies for millennia, e.g. the military ones. Illiterate peasants had no trouble with legion, cohort, centuria, contubernia.
I wonder if the cognitive problem is that the classic file system is an ungraded, unlimited hierarchy - all folders are equal, and you can not find a folders "grade".
Perhaps we would have been better off with an artificial limit of four or six named levels. Instead we're getting the hierarchy removed from general use devices ...
(Leaving aside the "use a hash, not a tree" possibility.)
With the unix filesystem, "/" is the quintessential representation of the ungraded, unlimited hierarchy. Once I understand what you mean by the word "root," and that root is represented by "/", I can intuitively understand this hierarchy.
With Windows, this "ungraded, unlimited" nature is terribly obscured by the Drive metaphor, as well as the creation of special "My" folders and libraries. In my experience, most users never venture out of these special folders to explore the rest of the filesystem. It's little wonder, now that I think about it, that this is so difficult for users: most never see the filesystem as a real hierarchy, only as the segmented randomness of the "My Computer" window. Mac OS is slightly better, but still retains many of the same metaphors through the styling of the initial Finder window and the home directory.
Perhaps the issue is not one of conception but simply the UX that serves as educator for these basic ideas.
I usually rephrase this as "your Dropbox folder is in the My Documents folder" which they DO understand because they're used to making folders and files inside of other folders.