Dave Burt wrote: > Trans wrote: >> Somone else mentioned this. Is it true? > > This says Module#included " should be used in preference to > Module.append_features if your code wants to perform some action when a > module is included in another." > > http://www.ruby-doc.org/core/classes/Module.html#M000704 > > Cheers, > Dave module M def self.included(klass) puts "Included in #{klass}" end end class A include M # -> Included in A end class B M.append_features(self) # Nothing end As you can see, Module#append_features doesn't call the .included method on the module, include does. Cheers, Daniel