[1.7.x] Fixed #1349 -- Clarified docs on serving files from STATIC/MEDIA_URL.

Backport of fb7c347f from master

docs/howto/static-files/index.txt

@@ -75,6 +75,7 @@ details on how ``staticfiles`` finds your files.
     by putting those static files inside *another* directory named for the
     application itself.
 
+.. _serving-static-files-in-development:
 
 Serving static files during development.
 ========================================
@@ -108,6 +109,8 @@ this by adding the following snippet to your urls.py::
     folder; it doesn't perform static files discovery like
     :mod:`django.contrib.staticfiles`.
 
+.. _serving-uploaded-files-in-development:
+
 Serving files uploaded by a user during development.
 ====================================================
 

docs/ref/settings.txt

@@ -1723,7 +1723,8 @@ Default: ``''`` (Empty string)
 
 URL that handles the media served from :setting:`MEDIA_ROOT`, used
 for :doc:`managing stored files </topics/files>`. It must end in a slash if set
-to a non-empty value.
+to a non-empty value. You will need to :ref:`configure these files to be served
+<serving-uploaded-files-in-development>` in both development and production.
 
 Example: ``"http://media.example.com/"``
 
@@ -2851,6 +2852,10 @@ If not ``None``, this will be used as the base path for
 
 It must end in a slash if set to a non-empty value.
 
+You may need to :ref:`configure these files to be served in development
+<serving-static-files-in-development>` and will definitely need to do so
+:doc:`in production </howto/static-files/deployment>`.
+
 .. setting:: STATICFILES_DIRS
 
 STATICFILES_DIRS