I have done this once, when I started in a middle-management role. During the first weeks, I was introduced / introduced myself to a couple of dozen people in v

I have done this once, when I started in a middle-management role. During the first weeks, I was introduced / introduced myself to a couple of dozen people in various capacities with whom I would need to collaborate. I kept a text document in which I listed who's who and what's what, and what their relation was to the organization I worked for. Nothing too fancy, just names, organisations, contact info and a few keywords. It's a useful exercise to do at the start of a new position for several reasons. For instance, you want to ensure you didn't skip or include the wrong people when sending out an e-mail. Or you have to attend, or organize, a meeting, so you want to know who's going to sit around the table and how they tie into the goal of the meeting is. When the lay of the land shifts fundamentally, it's useful to revisit the exercise. If you're in a purely operational role and your territory doesn't extend beyond your team or your office floor, there's not much point in doing such a formal exercise.