Desktop Metaphor Shortcomings
For active reading tasks the desktop metaphor has several shortcomings. The first is that the desktop metaphor usually involves many separate programs. Text editors, images viewers, video players, etc. This would violate the normally seamless environment which people expect from books. This seamless environment should be maintained even though more active media will be present in a digital library environment. The second problem with the desktop metaphor is that it is not spatial. Paper is a spatial environment, a person can write anywhere on the paper, even on top of items which are already present on the paper. This is very important for highlighting and annotation. Highlighting obviously has to go on top of existing text, while annotation may need to cross over existing items. For example, I may write a comment in the margin and then draw an arrow to point to specifically what I am commenting on. Another problem with the desktop metaphor is that it is based around files and directories. This is not a very natural way to deal with books and other contents of libraries, if for no other reason than it goes against the current and long standing feel of libraries. Given all these problems, a new metaphor may be in order.