A couple months ago, there was a formal usability test of wikipedia; it turned up a few problems, one of which stood out as both severe and easy to fix. Quote from the pdf, minus graphics -- http://openusability.org/download.php/89/germanwikipedia_usabilitytest_edit… -- - - - - - - - - - - Two users who started their first-time editing with a paragraph instead of the whole page were not confused by the syntax. However, they were faced another problem: The location of the "Edit" links seemed to relate them with the paragraph above, not the one below. Therefore, when clicking the "Edit" link below "Geschichte", they expected to see the heading "Geschichte" and its contents. This expectation was not met, instead "Weblinks" appeared in the editor window. They were confused, did not know what to do. Finally, both participants deleted (!) the existing and valid text, and started to add their own text. - - - - - - - - - -