diff --git a/README.md b/README.md
index 0a32770..dadcdc0 100644
--- a/README.md
+++ b/README.md
@@ -104,6 +104,13 @@ Set to 1 to redirect to libravatar.org if the user is not found.
 
 Default: 0
 
+### Things to keep in mind
+
+libravatarserv resizes images on the fly and does not cache anything. It also
+calculates both MD5 and SHA256 hashes for every user on every request. This
+could seriously strain the ressources of your computer if many users use the
+service.
+
 ## Install
 
 ### Gentoo