diff --git a/modules/README.txt b/modules/README.txt
index f4e35b5..53caca2 100644
--- a/modules/README.txt
+++ b/modules/README.txt
@@ -1,4 +1,13 @@
 
-This directory should be used to place downloaded and custom modules
-which are common to all sites. This will allow you to more easily
-update Drupal core files.
+This directory should be used to keep downloaded and custom modules that extend
+your site's functionality separate from Drupal core, encouraging best practices
+and facilitating safer self-contained code updates.
+
+In multisite configuration, modules found in this directory are available to
+all sites. In addition to this directory, shared modules may also be kept in the
+sites/all/modules directory for historic and compatibility reasons; the
+sites/[instance]/modules directory pattern should be used to restrict modules to
+specific site instances.
+
+Refer to the DEVELOPING FOR DRUPAL section of the README.txt in the Drupal root
+directory for additional information on extending Drupal with custom modules.
diff --git a/profiles/README.txt b/profiles/README.txt
index 2bbf4c9..121ff05 100644
--- a/profiles/README.txt
+++ b/profiles/README.txt
@@ -1,4 +1,26 @@
 
-This directory should be used to place downloaded and custom profiles
-which are common to all sites. This will allow you to more easily
-update Drupal core files.
+This directory should be used to keep downloaded and custom installation
+profiles separate from Drupal core profiles, facilitating safer self-contained
+code updates.
+
+Installation profiles define installation steps (such as enabling modules,
+defining content types, etc.) that run after Drupal's base installation when
+you first install Drupal and are what developers create as the basis of
+distributions.
+
+In multisite configuration, installation profiles found in this directory are
+available to all sites during their initial site installation, however modules
+and themes located inside a given profile are only available to sites that
+installed with that specific profile. In addition to this directory, common
+profiles may also be kept in the sites/all/profiles directory for historic and
+compatibility reasons, while the sites/[instance]/profiles directory pattern
+should be used to restrict themes to specific site instances.
+
+Read about the difference between installation profiles and distributions:
+
+* http://drupal.org/node/1089736
+
+Community-contributed installation profiles and distributions may be downloaded
+freely from Drupal.org at:
+
+* http://drupal.org/project/distributions
diff --git a/themes/README.txt b/themes/README.txt
index e942521..6432e4f 100644
--- a/themes/README.txt
+++ b/themes/README.txt
@@ -1,4 +1,13 @@
 
-This directory should be used to place downloaded and custom themes
-which are common to all sites. This will allow you to more easily
-update Drupal core files.
+This directory should be used to keep downloaded and custom themes that improve
+the appearance of your site separate from Drupal core themes, encouraging best
+practices and facilitating safer self-contained code updates.
+
+In multisite configuration, themes found in this directory are available to
+all sites. In addition to this directory, shared themes may also be kept in the
+sites/all/themes directory for historic and compatibility reasons, while the
+sites/[instance]/themes directory pattern should be used to restrict themes to
+specific site instances.
+
+Refer to the APPEARANCE section of the README.txt in the Drupal root
+directory for additional information on theming.