The principle of local structure is that every page or document or screen that you look at is self-contained and internally consistent, and that you don't need to refer to or understand the greater whole to appreciate one part.

Based on a conversation with Jerry Michalski and Lou Rosenfeld - I may have misplaced their approach to it - and the top paragraph is subject to revision until it's right. Ed

A wiki that has local structure would have every page in it be complete - or complete enough - so that you would not feel as if you had to rummage through or understand the whole thing to appreciate it. The wikipedia behaves this way, for the most part, with pages that are of roughly the complexity of encyclopedia articles. This wiki does not yet have local structure because there have been some hastily placed little nodes that don't make sense, yet, and no wiki gardening has gone back to fix them.

The Brain as practiced by Jerry Michalski is a great example of local structure - Jerry has a rough and ready map in his mind of how things fit together, and he knows how to garden them together to make it make sense. Alas, it's a single user application.

Most calendar pages have local structure - there's some unambiguous sense of what the scope of a page of someone's paper day-timer (does anyone use those still) and there are hard boundaries around the edge. (In fact, many people's calendars are messy and have scribbles of all kinds of things, so this may well be an overstatement).

Ed
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Hmmm, but this local structure is very context dependant. A page (or whatever) is only self-contained if the people reading it bring with them all the background knowledge required to understand the page. Ultimately you have to assume that the reader knows something about what the page is about, and it would be perfectly possible to create a page which, without change, would mean two entirely different things depending on the reader.

Or maybe I've just misunderstood.

• Lindsay Marshall