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
The plan must anticipate all that is needed Ebenezer Howard set spinning powerful and city-destroying ideas: He conceived that the way to deal with the city’s functions was to sort and sift out of the whole certain simple uses, and to arrange each of these in relative self-containment. And he conceived of good planning as a series of static acts; in each case the plan must anticipate all that is needed and be protected, after it is built, against any but the most minor subsequent changes. Jane Jacobs, The Death and Life of Great American Cities Same name in the same basket planningfunction