diff --git a/netconn.go b/netconn.go
index c43d3a29650b0c3e2746c7b18d4e982124f8d507..2db1f11e4187ff54f125168e3a7dc91c29247383 100644
--- a/netconn.go
+++ b/netconn.go
@@ -12,6 +12,11 @@ import (
 
 // NetConn converts a *websocket.Conn into a net.Conn.
 //
+// It's for tunneling arbitrary protocols over WebSockets.
+// Few users of the library will need this but it's tricky to implement
+// correctly and so provided in the library.
+// See https://github.com/nhooyr/websocket/issues/100.
+//
 // Every Write to the net.Conn will correspond to a binary message
 // write on *webscoket.Conn.
 //