The "Reply to This" and "Parent" buttons when viewing posts do not look like buttons. Buttons in every OS/GUI environment since Mac OS 7 have a simple 3d outline effect to give them the look of something "pushable." These buttons instead have a flat grey appearance which makes them look more like labels than something clickable.
Attached screenshot shows Slashdot buttons alongside typical buttons from various OSes (And one from Amazon.com.)
Screenshot:
http://schend.net/images/screenshots/slashdot/post_reply_buttons.png
Firefox 2.0.0.13 on Windows Vista
