It shows nothing more than the current battery charge (where "E" denotes an empty battery and "F" a full one).
It, like the Alarm Clock, can be collapsed. Once shown in its full shape and form, however, an additional button pops up. Clicking on the image of the Mac sleeping (with Zs coming out of the laptop) will make the portable go to sleep.
If network connections are active, the Macintosh will ask you to check network settings the next time the portable wakes up.