Recently, windows (e.g. MSN Messenger, Winamp) can be made translucent to the users' liking. This is probably more of a wow-effect than actual usefulness. However, one can imagine using translucency to make all windows visible when the user wants to switch between them (see below). A window does not have to be uniformly translucent—one can make the dominant UI elements of the window more opaque than other less significant UI elements of the window.

Like translucency, transparency has also been under-explored. Watermarks, when used properly, can communicate information without requiring extra screenspace:

This is crucial because when every view in Haystack, large and small, can potentially require fetching remote data, it is desirable to be able to indicate background computation for each view using the same screenspace as the view. Below, the contact information for "David Huynh" is fetched asynchronously and displayed progressively as it becomes available. The background animation tells the user that the view is being computed.

by David Huynh