diff --git a/htdocs/BuildSystems.html b/htdocs/BuildSystems.html
index b5968a5..8213566 100644
--- a/htdocs/BuildSystems.html
+++ b/htdocs/BuildSystems.html
@@ -1055,7 +1055,7 @@ module<a name="daytoday"></a></h4>
 
 <p>
   Now send an e-mail to <a
-  href="thdltools-announce@lists.sourceforge.net">
+  href="mailto:thdltools-announce@lists.sourceforge.net">
   thdltools-announce@lists.sourceforge.net</a> telling users where the
   JWS binary release is, where the source code distribution is, and
   why they should upgrade or try it out.