diff --git a/FAQ.md b/FAQ.md
index 076ed60..60e940d 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -113,7 +113,7 @@ A: For immutable files this is true—the resulting capability will be the same
 
 **<a name="Q15.1_dedupe_dangers">Q15.1:</a> Isn't deduplication dangerous? Can someone figure out whether or not I have a certain file?**
 
-A: to be added
+A: It is dangerous, even more so than most people realize! But, Tahoe-LAFS provides a defense: source:git/docs/convergence-secret.rst.
 
 **<a name="Q16_move_node_to_different_machine">Q16:</a> If I move the client node base directory to different machine and start the client there, will the node have the same node ID as on the previous machine?**