mention how to zwrite a user; add an aside about zephyr triplets

diff --git a/doc/zephyr.mdwn b/doc/zephyr.mdwn
index 2dc6fcba46a5ac6f07f28ccc8d1203389d3c7e27..7d892ea5fe87b856f489df8ce57558db31bf96be 100644 (file)
--- a/doc/zephyr.mdwn
+++ b/doc/zephyr.mdwn
@@ -86,6 +86,20 @@ instance with the -i option to zwrite:
 A message without an instance specified will default to the instance
 “personal”.
 
+You can send zephyrs to individuals (as opposed to classes) with:
+
+    :zwrite USERNAME
+
+### Aside: zephyr triplets
+
+All messages are actually sent to a "zephyr triplet" -- a class, instance, and recipient. Subscriptions are also made to zephyr triplets. The recipient can be either "*" -- to indicate a broadcast message -- or a specific individual.
+
+When sending, the default class is "message", instance is "personal", and recipient is "*". `zwrite` supports sending to arbitrary triples with `:zwrite -c CLASS -i INSTANCE USERNAME` -- the two examples above use the defaults for the parts that aren't specified.
+
+For subscriptions, the class must be specified. You can specify all instances on a class with "\*", or specify just one instance. You can only sub to recipient "\*" or your own personals (indicated by "%me%").)
+
+### Common classes
+
 Some common classes include:
 
 <strong>help</strong>: