Once more; this is graph theory and graph traversal, it's a well defined  part of Computer Science with extensive underlying mathematical principles.  I'm not sure that means all IT professionals need to understand it.  I've worked with many great UI and UX pros and many Business Analysts who really have no need of it.  However, if you are doing anything that touches algorithms then yes you need to at least know the basics.  If you're designing data structures you should at least know what differentiates a graph from something that is not a graph and why that matters (ie; relational databases vs. key value stores).  Unfortunately the reality is that this stuff is pretty abstract and hard to teach.  Bridging the gap from the pure theoretical to the hands on building of programs that are used to teach computer languages isn't really done.  We've touched on it previously before on the list, but to me this is the dividing line between "programmers" and Computer Scientists.  I don't think you always need the latter, but I do agree that the world in general needs to know the difference and why it matters.