Just click those rectangular objects at the top.
An idea for the Notification Page. The numbers next to the icons would indicate how many of that notification you got during that day or since you last checked. Since Comments are probably the notification you care most about, it's the default shown (and the only number indicated at the top of the web page). I would assume that being able to change some options to customize it would be a good idea as well. But the discussion is here: http://scratch.mit.edu/discuss/topic/5952/
