Wiki might not work for that becouse first somehow you must decide who would be the users, it might eather creat way too big group of people with easy way to get in and spoil any important data or isolated community with lack of new, fresh and impotent entries. Modern market are changing in great speed every day so we cabt put ourselfes into small chamber with no dors, witch would be closed group on such wiki.

Ofcourse there is nothing that would stop any one from creating such option for others, but i personally would rather ignore such option.