Windows 7 introduced the concept of Libraries. Like symbolic links in Unix. I'd describe them as a layer of abstraction over the hierarchical directory system that most people have learned to deal with since DOS. It's not terribly hard to shove 'folders' down peoples' throats. They see filing cabinets filled with folders all the time. Hard drive = filing cabinet. Folders = subdirectories. Simple.
But Microsoft just had to give Windows 7 something more than a pretty face (like the Mac) and better security (like the Mac.) So it added a file system abstraction that aggregates folders from different places and/or computers into the mix. When you delete something here it isn't deleted from the source. When you copy something here there aren't really two copies of it. More properties control the listing order and the new indexing service can be enabled to search by more metadata.
Trouble is 100% of my customers don't care. Actually, 100% of the comments on the Microsoft website explaining this little gem of a feature want to know how to make it just go away!
Don't they pilot this stuff? Or do they just not listen? We've reached the stage where the Windows operating system has simply morphed into an engineer's feature dreamworld. One would think they'd focus on the user's productivity.