The Principle of Least Astonishment, is the principle that you should plan your pages and links so that everything appears reasonable. If a link doesn't take a surfer to where they thought it would, it should at least take them someplace that makes sense.

Example:

"Lincoln is key to the economy of the central states."

Does "Lincoln" refer to Lincoln, Nebraska or to Abraham Lincoln or, best of all, to a page giving the surfer a choice among many Lincolns?

Another example:

A user wants to know about the nuclear power plant that exploded in Chernobyl. The page on "Chernobyl" redirects to "Chornobyl," the appropriate spelling for that town. However, the user sees that a link to the desired page, Chernobyl accident, is placed prominently near the top of the Chornobyl page, and happily clicks on that.

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