improved the comments.

playbooks/roles/edx_service/tasks/main.yml

@@ -12,13 +12,19 @@
 # Tasks for role edx_service
 # 
 # Overview:
-# 
 #
-# Dependencies:
+# This role performs the repetive tasks that most edX roles
+# require in our default configuration.
 #
-# 
 # Example play:
 #
+# Rather than being included in the play, this role
+# is included as a dependency by other roles in the meta/mail.yml
+# file.  The including role should add the following
+# depency definition.
+#
+# dependencies:
+#   - { role: edx_service, edx_service_name: "hotg" }
 #
 
 - name: create application user