I think it would be great for div's/img's to get some of the functionality that "layers" have in photoshop.
Right now, using .png's, div's/img's/etc.'s have their RGB and alpha values. If you have a 50% transparent layer on top of an 100% opaque layer, the resulting color is a 50/50 blend. Similarly, if you have a 100% opaque layer on top of another 100% layer, the top layer is the only one that shows.
In photoshop, however, you have blending modes -- multiply, color dodge, screen, overlay, soft light, et al. -- all of which blend the layers using methods different from the method described above.
I made a web site that has a spotlight on the page, but I won't be able to light up the dynamic content that it's pointing at (unless I use JS to do so) because the only blending mode available to me is the "normal" RGB*A method. There is no option to blend a gobo (picture of the light) using a color dodge, overlay, or soft light method.
Is this a feature that will be coming out soon to any web browsers?