PowerPointTM Skirting the Edge - Information
No information should go all the way to the edge of your slide. Remember that your image will be projected in front of an audience, and the audience will focus on only about one third of the slide at a time. Keep minute details to a minimum, and keep the focus to the central part of the slide.
How often do you watch what's going on at the edge of your TV screen? You notice it only when something has been cut off. Avoid this mistake.