Under KDE, I can add 'comments' to any File/folder. I consider it the digital analogue of 'sticky notes' on physical files. Can I get the same/similar behaviour in Unity/Gnome?
If yes, how? If no, why?
With the old and "dead" Gnome2 there was a possibility to add notes to a file or folder through the properties window. There was a dedicated tab for this. Now with Gnome3 this functionality is gone. I don't know if there is a Nautilus add-on for this, or if in the future Gnome3 will include this again.