Picasa Web Albums has a new zoom viewer that uses Flash. If you click on the magnifying glass icon next to a photo, you can select a rectangular region from the image and zoom in or zoom out. The feature is called "microscope zoom" and it doesn't fall back to the old version for users who haven't installed Adobe's Flash plugin.
Another new feature lets you view all the EXIF tags that are available by clicking on "full details page". You'll find a lot of tags that offer more information about white balance, orientation, exposure, color space, brightness, light source and more.
{ Thanks, Bogdan. }