Wiki is the simplest collaborative environment that could possibly work --- and it does! "Wikiwiki" means "quick" in Hawaiian. A Wiki is a set of Web pages designed for extremely rapid evolution and extraordinarily productive use.
Wiki was invented by Ward Cunningham in 1994. The book The Wiki Way" Quick Collaboration on the Web by Bo Leuf and Ward Cunningham (Addison-Wesley, 2001) explains Wiki and provides a stand-alone highly-customizable Perl-based Wiki server which runs on almost any computer system.