While moving stuff around in the Tamriel worldspace it often happens that you alter a cell without doing anything substantial to it. For example you drop a static in the render window and move it to the next cell where you place it - the cell you've dropped it in will be marked as altered even though it's completely unchanged and thus you create a somewhat dirty edit. With TES4Edit you could easily clean your plugin after you were done with it and remove unnecessary cell edits with a single click. Is there a tool for Skyrim yet that does the same?
TES5Edit is in the works, until then, we'll probably just have to live with it. The CK isn't nearly as bad about dirt as previous incarnations were though.