diff --git a/doc/developers/TODO b/doc/developers/TODO
index 57805c3..59dd655 100644
--- a/doc/developers/TODO
+++ b/doc/developers/TODO
@@ -9,6 +9,9 @@
 - use recaptcha or alike -> quickform
 - tutorial about sidebar
 - update php-gettext
+- index on bookmarks->modified, since created is not used in selects/sort
+  - how to optimize sorts, to prevent mysql filesort? -> index enough?
+  - how to optimize DISTINCT bHash
 
 
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