In some ways, it is more helpful to
think of Zotero’s database as a robust
folder system. Each folder can contain
many subfolders, and items can be
dragged between folders or exist in
more than one folder at a time. The
folder system is optional; users are free to
put all of their items in the same folder
and rely on one of the organizational
systems such as the Web 2.0 tagging that
allows for the possibility of a customized