[quote=Kafka Komedy]
I think I get it. It's like every world you get a new skill tree based on that world, and you have the choice of investing more in one of the skill trees each world.Did I get it right?
[/quote]

Yep pretty much. 
Another idea I have is that we could have two, uhm, points, I guess, and those points can either be used to invest in a new basic first tier skill, for the current world, or further earlier abilities.