ThatsBoBo - 8:45 pm on Apr 4, 2012 (gmt 0)
@ netmeg, ken_b, Lame_Wolf
Do you have the option selected to review placement ads before letting them run? If so, try changing it to the let placement ads run right away option and see if the new "shown ads" feature appears.
I've heard this may be a bug, but can't confirm from my current location.