Not just Maybe

http://haskell.org/wikisnapshot/NotJustMaybe.html

Note: Many now consider the fail method of Monad to be a failure, as it defaults to throwing an exception. Modern Haskell style tends towards using total functions wherever possible, and this idiom has come increasingly to be frowned upon.

A more recent page than the wikisnapshot can be found in the Web Archive: [1]