Visual not logged

i visited listal without login and i noticed that in the lists pages,
at the right column, there is an empty space, what is it for?

in my specific list, i tried to arrange a group of images to make the page visually better(more impact ;) and that empty space...mmm don't sounds good XD

The blank space is where a advert would usually be displayed (google adsense) but is blank where there is no relevant ad to display for that page.

thanks for responce...
anyway i thought about my question and is not really relevant for 2 motives:
1-who is logged not see the empty space
2-if someone vote the list, automatically appears a bar that pushes down objects in the column.

then to resolve the problem should change different things as the ad space and vote bar position but don't worth