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

• a cool tall drink of water might have no friends defined. If you are a cool tall drink of water, you can edit your InsaneJournal friends so they show up here.
• a cool tall drink of water 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.
• a cool tall drink of water 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.