Some usability feedback: It seems like the most useful information is contained in the links between nodes, but at first it was not obvious to me that they were

Some usability feedback: It seems like the most useful information is contained in the links between nodes, but at first it was not obvious to me that they were clickable, or that clicking the text links at the bottom of node descriptions would actually show the 'link' description, rather than just taking me to the next node. I'd recommend you make it clearer that the linking lines between nodes are clickable. Even better, rather than using a modal dialogue to display node contents, you could use a popover with an arrow pointing to it's owner. Clicking a link a the bottom of an item would simply move the popover, making the relationships between various items of content clearer.