One of my favorite ways to get ideas out of my head is to start scribbling on a whiteboard. I love to make lists, draw diagrams, and connect things with arrows. It is wonderful for in-person collaboration too.
Whiteboards are great, which is why most offices have a few of them.
Whiteboards are generally a shared resource. And that can quickly become a problem. Now, I'm going to stop myself before I go down the path of some convoluted analogy about resource allocation, pointers, and modifying shared memory. I think many people can think of a time when they sketched a bunch of stuff out on the whiteboard and the next day it was just gone. All those ideas just gone.
Someone erased your hardwork. They probably didn't realize they were doing it. "That looks like the stuff that's been on this board for weeks," they thought to themselves.
Here is the best way I've found to deal with this issue. First, create a channel in your organization's communication tool called something like whiteboardin'. Then the next time you need to use a covered whiteboard, snap a quick picture and post it in that channel. The high-resolution photos that everyone's phones can take make it easy to zoom in to every detail. You no longer need to worry about tracking down the person who previously used it to see if they need a saved copy -- just assume they do and post it.
Get your whole organization's buy-in on doing this. Perhaps even post signs next to the whiteboards as reminders, "Before you erase..." Today you'll be saving someone's work, next week someone will be saving your work.
You might be wondering, why not put the impetus on the person who originally used the whiteboard to save their own scribbles if they are so important. I prefer the approach I've outlined because it creates a more cooperative mindset. It encourages empathy and values the work and time of your coworkers.
Save yourself some time, save your coworker's work, and get to whiteboarding before those ideas slip away.