At the last place I worked at, I learned about a cool thing people could and did do when they transitioned out to other companies.
As in a lot of places, their semi-annual review process included peer feedback to help your manager to see your impact, to get additional insight, and in many cases for others to show appreciation. Technically, you could submit this feedback at any time, but most commonly it was done during the review crunch.
I always made a point to take some time and put in 2-3 bullets of genuine impact statements, as in not just activity but results. It was nice to find out that my words were appreciated, too. I had the pleasure of being cornered by one of our attorneys after one bit of feedback, and he said it was the highlight of his review (which surprised me, he was a good dude and competent–he’s a director now).
For my last week, I sat down and wrote a number of these for people I appreciated who had made my job easier or were just damned good at what they did. Apparently receiving out of band feedback like that was also jarring to them, as in “it didn’t really hit me that you were really leaving until I got feedback from you, so now it’s real.”
I don’t know that there’s a point to this, other than to commit an experience to text. I’d encourage anyone who has the ability to submit this kind of feedback to folks out-of-band to do so. It can really matter, and especially so for people like myself who don’t toot their own horn loudly as some might.