Starfish, leaving a small note on messages is really easy...
You probably just didn't notice it...
When you click on a certain post, you will goto a page where the message is contained...
Below the message, you will see 3 boxes...  two small ones on left and right... one big one in the center...  The first box on the left is for you name, the longer one in the middle is for a short message, and the very right box is for yur password...
after entering in all the boxes, you can click to post your short note...

Or, all this could sound all weird...
In such a case, it could be that this board isn't showing up correctly in your computer...
We would have to do something else to work around that, because you could be using an uncompatible version of a browser, or using an old Mac OS...

But, if you can see those boxes at the bottom of every message, you should be able to add notes on them...  I hope it works out.. ^^

Always take care...
and... boy...JiWoo sure looks beautiful in the new photos..hehe