There are a few reasons why you might not see posts on this friends page:

• Quotes of the Day might have no friends defined. If you are Quotes of the Day, you can edit your LiveJournal friends so they show up here.
• Quotes of the Day might have friends defined, but all of their friend's posts might be over two weeks old (according to the times on our servers), and thus wouldn't be displayed here.
• Quotes of the Day might have friends defined that post only protected entries that you can't view, because they haven't defined you as a friend in return.