diff --git a/src/docs/userguide/remarkup.diviner b/src/docs/userguide/remarkup.diviner
index 0e356d5352..7d338a8ef1 100644
--- a/src/docs/userguide/remarkup.diviner
+++ b/src/docs/userguide/remarkup.diviner
@@ -132,4 +132,13 @@ You can upload image macros (Files -> Image Macros) which will replace text
 strings with the image you specify. For instance, you could upload an image of a
 dancing banana to create a macro named "peanutbutterjellytime", and then any
 time you type that string it will be replaced with the image of a dancing
-banana.
\ No newline at end of file
+banana.
+
+= Mentioning Users =
+
+In Differential and Maniphest, you can mention another user by writing:
+
+  @username
+
+When you submit your comment, this will add them as a CC on the revision or task
+if they aren't already CC'd.
\ No newline at end of file