I wanted to share some free, yes I said free, software that helps me keep many a detail straight for my current campaign. Some of you out there are probably quite familiar with mind mapping software and what it can do. I personally use VUE to map out all of my PCs relationships to each other as well as all of their relationships to NPCs (i.e. contacts, allies, and enemies). It helps me out in a pinch when my players go sideways instead of forward. Here are a few rough pictures of some data to highlight its usefulness. The nice thing is VUE is built for both PC and Mac.
Cheers!