diff --git a/README.md b/README.md
index 5c4cd7d..a865b60 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,7 @@
 # le-store-SPEC
-The specification, template, and tests for creating an le-store- strategy.
+
+The reference implementation, specification, template, and tests for creating an le-store- strategy.
+
+The reference implementation is completely in-memory.
 
 See [Help Wanted: Database Plugins (for saving certs)](https://github.com/Daplie/node-letsencrypt/issues/39)