I'm not sure of what the problem is. However, I upgraded many components on the site over the past few days. It's possible that one of the upgrades changed the behavior of this. Lets monitor this for a week or so to see how it really works.
One thing I noticed is that if you set the menu at the bottom right to "today", and click "GO" it shows only todays posts. However it doesn't keep this after you close your browser and come back.
Another thing I noticed is that as long as you are logged in (and keep yourself logged in), you will see the bahavior you describe. Then the only indication of new posts is the tiny orange squares. However if you log off (by clicking the log off button), you reset this and then you list will be empty when you log back in.