The problem with trees Many systems are organized hierarchically. The CERNDOC documentation system is an example, as is the Unix file system, and the VMS/HELP system. A tree has the practical advantage of giving every node a unique name. However, it does not allow the system to model the real world. For example, in a hierarchical HELP system such as VMS/HELP, one often gets to a lead on a tree such as: HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS only to find a reference to another leaf: Please see HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS and it is necessary to leave the system and re-enter it. What was needed was a link from one node to another, because in this case the information was not naturally organized into a tree. Tim Berners-Lee, Seeing With Fresh Eyes A City Is Not a Tree hierarchywww
Cool URIs don't change An Essay by Tim Berners-Lee www.w3.org What makes a cool URI? A cool URI is one which does not change. What sorts of URI change? URIs don't change: people change them. The User Interface of URLs www
Class 1 / Class 2 Problems An Article by Kevin Kelly kk.org There are two classes of problems caused by new technology. Class 1 problems are due to it not working perfectly. Class 2 problems are due to it working perfectly. ...Class 1 problems arise early and they are easy to imagine. Usually market forces will solve them. You could say, most Class 1 problems are solved along the way as they rush to become Class 2 problems. Class 2 problems are much harder to solve because they require more than just the invisible hand of the market to overcome them. ...Class 1 problems are caused by technology that is not perfect, and are solved by the marketplace. Class 2 problems are caused by technology that is perfect, and must be solved by extra-market forces such as cultural norms, regulation, and social imagination. problemstechnologyculturesociety