Ooooh - this is a great thread. I know that everyone I edit for original reviews (vs. follow-up) gets a note from me on the review with the changes I made - plus if they aren't an advanced reviewer - I also give them information about the two ways to become an advanced reviewer along with links to the mentor page and I try to stress the benefits of having a mentor. I'd share one here - but I actually personally write each one to that person.
I also give them tips for their next review of a product like that - for instance - if its a vibrator and they didn't talk about material or how to clean it, I'll mention that.
I'm curious to see what the other editors do/did!