diff --git a/README.md b/README.md
index 3f67274..810c088 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,10 @@ The matrix.to URL scheme is
 The #/ component is mandatory and exists to avoid leaking the target URL to the
 server hosting matrix.to.
 
+There is no _Entity type_ for **Spaces**, as they are technically really just regular
+rooms. (Some servers call their "entrypoint" space literally `space`, in which case
+the URL would be `https://matrix.to/#/#space:example.org`.) 
+
 Note that linking to rooms by ID should only be used for rooms to which the
 target user has been invited: these links cannot be assumed to work for all
 visitors.