Shutter glasses, together with appropriate driver software, let you view your games or other 3D applications in proper, genuine 3D. Each eye sees a different image. Back then, the Asus driver support for the glasses was lousy. But the hardware limitations remain. Shutter-glasses work by rapidly alternating two images on the monitor, one for each eye, and blacking out the lens in front of each eye in turn so that each eye only gets to see the image that's meant for it. Now, that's great in theory, but in practice LCD panels can't black out completely.
Some light always gets through.
So each eye sees the image that's meant for it, but also sees a dim ghost of the image that's meant for the other eye. The result's an odd triple-vision sort of effect. To get that refresh rate out of most current screens, you need to run in a relatively low resolution. Which puts a bit of a damper on the pretty-factor. So you'll like 'em, if they're the sort of thing that you like.