Plan for transparency?

[Andrew Conkling]

Since it's obvious that Xfce is taking advantage of the compositor
extensions of XOrg's 6.8.0 release, I was wondering if there was any
plan for using its transparency also?  For instance, when I'm using the
notes panel plugin, I'd like my notes to appear slightly transparent. 
Or, I'd like to be able to make a window transparent without affecting
the xfwm4 borders (like an xterm window).  Or, etc.

How much of this should be controlled by the application in question,
and how much should be the wm's responsibility?

Andrew