A friend of mine sent out an SOS on Twitter because she couldn't figure how to use a certain feature. She got an immediate response from another Twitter user detailing what she needed to do. At the bottom of the email was a "P.S. I'll never forget how kind you were to me in that transaction many years ago when I was first starting ... "
1. When you are kind, people remember - even years later
2. It's so great to get to help someone who helped you (I pounce on those opportunities too)
3. Adding a positive "P.S. I'll never forget ... " is a nice way to communicate you haven't forgotten
What goes around, comes around - even kindness.