Windows installers generally use the Windows API to find out the real names and locations of the Start menu and Desktop folders.
On Windows XP systems, the root of this namespace is the Desktop virtual folder, which contains the My Documents, My Computer, My Network Places (Network Neighborhood in Windows 95 and 98) and Recycle Bin virtual folders.
The Desktop virtual folder is the root of the Windows Shell namespace, which contains other virtual folders.
So, out of the box, your home folder, when docked, appears to be the Desktop folder.
And those few items may be misleading (e.g., the home folder appearing to be the Desktop folder) or completely generic (e.g., the Pictures and Movies folders showing up as plain folder icons.)
For example, a user's Home folder shows the Applications folder (or if that does not exist in Home folder, the Desktop folder), while the Photos folder is just a "stack" of plain blue folders created by iPhoto.
For example, both types of profiles can be redirected to use a single Documents folder, and a single Desktop folder, so that the user's account documents are consistent between the two profiles, even if all other account settings will be different.
The universal Desktop was gone, replaced by a Desktop that presented only the contents of the user's own Desktop folder.
A more frustrating issue is that the file manager doesn't seem to show you files on the desktop anymore, even though it still created a Desktop folder in my home directory.
The "Desktop" folder is by far the most interesting item.