diff --git a/walled garden.md b/walled garden.md
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--- a/walled garden.md	
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@@ -1,4 +1,5 @@
 # walled garden
 
-- a [[platform]] that tries to maintain centralized control over content and users.
+- a [[system]] or [[platform]] whose owner that tries to maintain centralized control over content and users.
+  - [[wp]] https://en.wikipedia.org/wiki/Closed_platform