diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b8914514d7..c0dd2394e3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -41,7 +41,7 @@ Please do not suggest to add domains from the blacklist. They're banned for the
 * cet.edu - this one's best. It could forward e-mails to your gmail.com even without registration. Cool.
 * australia.edu - anyone could register e-mail account there
 
-
+We intentionally exclude alumni domains (like john.smith@alumni.stanford.edu) as well.
 
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