Have you looked at the Activity Overview:

or Tracking Values:

it is not accessible by default... but if you really want to see them, you can activate the debug mode, go to the technical menu, click on the models sub-menu in database structure section, once in there, search for the "mail.message" model (it encompasses all the messages on the chatters), then you can scroll down at the bottom of the view and click on "create menu".. you can put it anywhere you want to, but just choose correctly the right parent... 

Hope it can help