Clarify notifier bullets

This commit was SVN r21169.

NEWS

@@ -35,12 +35,13 @@ Trunk (not on release branches yet)
 1.5
 ---
 
-- Added twitter notifier component.  See "ompi_info --param notifier
-  twitter" for a list of the relevant MCA parameters that are
-  necessary.
-- Added smtp notifier component (requires libesmtp).  See "ompi_info
-  --param notifier smtp" for a list of the relevant MCA parameters that
-  are necessary.
+- Add several notifier plugins (generally used when Open MPI detects
+  system/network administrator-worthy problems); each have their own
+  MCA parameters to govern their usage.  See "ompi_info --param
+  notifier <name>" for more details.
+  - twitter (yes, that Twitter) to send a Tweet.
+  - smtp (requires libesmtp) to send an email.
+  - command to execute arbitrary commands (e.g., run a script).
 
 
 1.3.3 (expected)