diff --git a/underlays/basewiki/directive/aggregate.mdwn b/underlays/basewiki/directive/aggregate.mdwn
index b8814a049..6173f3944 100644
--- a/underlays/basewiki/directive/aggregate.mdwn
+++ b/underlays/basewiki/directive/aggregate.mdwn
@@ -1,5 +1,8 @@
 The `aggregate` directive is supplied by the [[!iki plugins/aggregate]] plugin.
 
+This plugin requires extra setup, specifically, a cron job.
+See the plugin documentation for details.
+
 This directive allows content from other feeds to be aggregated into the wiki.
 Aggregate a feed as follows: