It used to be that I answered questions in this forum, but with this deluge of new features, I’m a newb again. I was playing around with displacement maps and ramp shaders today, and came up with this:
It looks really…bad.
I think I know how to use a ramp shader, but I don’t really know why it should be used. What are situations that call for their use, and in which modes?
Thanks much!
Matt
well, do you mean a colorramp shader on a material color, or specular color, or a blend texture mapped to whatever, or texture mapped to a colorramp ! 
cause you’re right, me too, so many new toys.
I just posted to the pingpong net thread a use of colorramp shader to alter the wood texture to give a butterfly net.
My mostest favoritest use of colorrramp is for flame where you have blue then red then yellow fading to alpha 0.
And then there is is a colorramp for fake SSS where you map one colorramp for color and then another for Specularity color, so that the reflected specular color changes as the incident angle changes. Also really cool for car undercoat colors.
and then there is the colorramp node…
In real life, especially for human skin, I think there is a natural effect where color changes when it is lighted brighter, maybe someone can confirm that? in some making of the Matrix interview someone explained that with real objects, light bounces around inside and comes out, like with skin which is very transparent, and in 3d you would need to compensate for that.
Another other major use is toon shaders or kind of half toon shaders for paint like effects.
And then transparent effects, it can affect alpha too. I should show some example images, I think ramp is a good thing to know.