diff -r 9c8d31d69044 Doc/library/__main__.rst
--- a/Doc/library/__main__.rst	Mon Jan 06 11:10:08 2014 -0800
+++ b/Doc/library/__main__.rst	Mon Apr 14 11:33:49 2014 -0400
@@ -5,13 +5,18 @@
 .. module:: __main__
    :synopsis: The environment where the top-level script is run.
 
+__main__ is the name of the scope in which top-level code executes.
+A module's __name__ becomes equal to '__main__' when read from
+standard input, a script, or from an interactive prompt.
 
-This module represents the (otherwise anonymous) scope in which the
-interpreter's main program executes --- commands read either from standard
-input, from a script file, or from an interactive prompt.  It is this
-environment in which the idiomatic "conditional script" stanza causes a script
-to run::
+A module can discover whether or not it is the __main__ module by
+checking its own __name__, which allows a common idiom for conditionally
+executing code in a module when it is run as a script or with `python
+-m` but not when it is imported:
 
    if __name__ == "__main__":
+       # execute only if run as a script
        main()
 
+Alternatively, a package may include a __main__.py module, the
+contents of which will be executed when the module is run with -m.