I get it in the most basic sense:
- There is a "skill family" level that represents your level of advancement within the entire skill family - when you advance this skill level, you get access to the higher level skills.
- There is a "skill-specific" level that represents your level of advancement in a specific skill. After you advance four levels, you can choose to morph that skill into something with extra effects, and then you can morph it again.
What I'm wondering is if those skill levels do anything more than just track whether you can add new skills. I ask that because the morphed skills *also* advance four levels -- so for example, my sorcerer currently has Thunderous Form II. Do the skill advancements do anything? Do they increase your damage or buff or spell duration? I assume they have to do have an affect beyond opening up skill lines otherwise there'd be no point in advancing them after a morph, but I haven't noticed anything that can't be explained by gaining class levels and increasing in power that way...