In the canonical usage, Domain Distortion is the name of the fractal in between the coordinates and the main fractal on a texture leaf kickstand. There are other ways to add distortions to textures, but we'll start with Domain Distortion first.

By far, the most common way Domain Distortion is used is to 'wrinkle up' altitude-driven blends. Snowlines, rock strata, beach lines - all of these look unnatural if they're too flat and the way to make them un-flat is with Domain Distortion.

Let's take the rock strata example first, because it'll also talk about another important texture leaf concept. We want to be working in a planet file with a simple but steep terrain with the contour line material on it.

In the diffuse color texture editor, make a new texture. Because the contour line texture leaves and blends are still in the file, it's a simple process to overlay those lines on top of the rock strata leaf we'll create first.

Enable the first texture leaf. Click to expand its kickstand. Name it 'rock strata'. Set the input to Altitude. For all the altitude-driven texture leaves we had in the contour line material, the Altitude output went through no distortion and no fractal to arrive at the Input Curve in its raw form. But for this particular leaf, in the Input Curve, set the Min Input to -0.7 and the Max Input to 0.7. Those aren't altitudes any more - they're the output of the Monofractal that's still sitting there in the fractal position of the kickstand. The fractal is using the altitude as its input but what comes out are "values between -1 and 1." Though from the Basis Function editor detour, we've seen that the actual output of the default basis function range is closer to -0.7 to 0.7... One last tweak - change the LFS in the Monofractal to 100 instead of 1000. This makes the rock strata thinner and is what I used for the sample images below.

This gives us a simple black-to-white rocky strata layer. Now enable the second leaf and use the DDLB to select the '200m lines' leaf from the contour line texture. Change the blend between the first two leaves to 'Blend' and again, use the DDLB here to change the default texture leaf to the '200m line blend' from the contour line texture. Note that the DDLB on the second leaf listed color texture leaves first then value texture leaves, but that the DDLB on the blend lists them the other way around. That's because the blend is looking for a value texture, not a color one - and vice-versa on the second texture leaf. It's up to you whether or not you want to enable the third leaf and set up the yellow 1Km lines or not.

With the contour lines in separate leaves, we'll be able to apply distortion to the rock strata leaf alone. So, we're in the rock strata leaf and changing the 'None' in the distortion position to 'Monofractal.' In the following image, there are actually three slices and I probably should have drawn in boundaries like I did on the Basis Function examples.

These layers still look pretty darned flat. The left third of the image has the default LFS of 1000 on the distortion fractal and the Result Scale has been set to 10 instead of 1. The middle slice has the LFS taken down to 100. The right-hand slice has the LFS taken down to 10. It's hard to see any difference in the three and all of them have the Result Scale set at 10. What that means is "shift the layers up and down by 10 meters". The varying LFS parameters are the distances between the 'waves' created by the Result Scale.

In this one, the three slices are much clearer. Again, the slices vary the LFS of the distortion fractal from 1000 to 100 to 10, but the Result Scale for all three here is 100.

Lastly, here's the exact same deal, but the Result Scale on the distortion fractal is set to 1000 in all three slices. As you can see, a distortion result of 1000 meters happening every 10 meters grinds those rock strata to pixel dust.

The general rule for distortions is - make the Result Scale of the distortion the same as the LFS on the fractal you're distorting (plus or minus an order of magnitude).