Deliberately choosing to over-expose a photo to create a 'high-key' effect results in a light and delicate look that can enhance feminine portraits and pictures of children.
The trick is not to blow the highlights in-camera, but rather brighten up the shot later in software such as Photoshop.
Shooting RAW files will give you the most editing head-room, as you'll be able to extract more detail across the tonal range in raw compared to JPEGs.
