diff --git a/plugins/xC/utm-filter.lua b/plugins/xC/utm-filter.lua
index bbf0dd9..b708c12 100644
--- a/plugins/xC/utm-filter.lua
+++ b/plugins/xC/utm-filter.lua
@@ -18,6 +18,9 @@
 -- A list of useless URL parameters that don't affect page function
 local banned = {
 	gclid        = 1,
+
+	-- Alas, Facebook no longer uses this parameter, see:
+	-- https://news.ycombinator.com/item?id=32117489
 	fbclid       = 1,
 
 	utm_source   = 1,