[Haskell-cafe] From monads to monoids in a small category

"Monads are monoids in the category of endofunctors" This Monoid instance for the endofunctors of the set of all elements of (m a) typematch in Haskell with FlexibleInstances: instance Monad m => Monoid (a -> m a) where mappend = (>=>) -- kleisly operator mempty = return The article can be found here: http://haskell-web.blogspot.com.es/2012/07/from-monads-to-monoids-in-small.h... I would appreciate some comments.