You're certainly right about that. But I also think the best way to learn really is to try something yourself. That of course makes certain assumptions that are not always (or even often?) true such as that you know how to try in the first place, that trying will not take a whole ton of time, and/or that you have a lot of time to try things. That being said I still think it's a good policy to take a stab at it first, *try* to try as a start, and if you fail or learn nothing, then ask. When it works it's a better, faster way.
The key is to have a clear testing method and time limit. Give yourself 10 minutes to figure it out (or 5 if you're really starved for time), and try just plugging in one each of a shader that outputs Color and one that outputs Displacement, and see what effect there is, if any. Those are the two main types of data in TG, and both are output by the Power Fractal, so you can literally test almost any non-Function shader by feeding a Power Fractal into it. Just make sure its Displacement setting is larger than the default of 1, maybe 100, so you can see larger-scale effects; it may be too much, but at least you'll see *some* effect. Also be sure High and Low output colors are enabled.
Anyway, as I said this is not to excuse any lack of documentation, that needs to be resolved too. But it doesn't solve everything. What is the first thing you're going to do once you read "The Crater Rim Shader input allows you to specify a displacement shader that only affects the crater rim or edge"? My guess is you're going to try it to see what that actually looks like in TG. A really impatient and/or clever user would thus try it first and seek further info if they weren't able to understand.
- Oshyan