diff --git a/.gitignore b/.gitignore
index 06a228128e..9767e52dd2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,9 @@
+# Don't add patterns to exclude files created by preferred personal tools
+# (editors, IDEs, your operating system itself even). These should instead be
+# maintained outside the repository, for example in a ~/.gitignore file added
+# with:
+#
+# git config --global core.excludesfile '~/.gitignore'
 AUTHORS
 ChangeLog
 *.pyc