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
A lightbulb is not an idea An Article by Ralph Ammer ralphammer.com With conventional placeholders, such as words, we can describe patterns for a large number of situations. On the other hand it is easy to fool yourself (and others) with words, since you can avoid to be specific. Any business meeting can confirm this. When you draw something you are forced to be specific — and honest. Our illustration of an “idea” from above is unconventional in the sense that it conveys specific original thoughts of what an idea is. It adds value to the words. And that is the catch: The drawing must be unconventional to support the conventional words. We have to make sure not to use “words in disguise”. Take a common illustration for “idea” for example, which haunts flip charts all over the world: the lightbulb. The lightbulb image works on a purely symbolic level, it only replaces the word “idea”. This image of a household item contains no original thought about what an idea is. While symbols like these work well as international replacements for words or icons to indicate a light switch for instance, they convey no nutritional value as illustrations — they are empty. wordsideassymbolsdrawing