My alernative to nested sets for arbitrary-depth hierarchical data sets: Good or Bad?

While recreating my CMS, I wanted an alternative to the traditional parent/child approach for managing the sitemap / page hierarchy. I had remembered seeing the nested set model a while back, but couldn't remember what it was called. So, I stumbled upon a similar approach that I want to evaluate and compare the properties, making sure I won't run into dumb limitations later on because I didn't go with what is already time-tested. So, please advise if A) it's already been invented (what's it called?!), B) there are fundamental flaws in the properties, or C) it's a good approach (please give good justification!).