I love reading the comments on the designs pages, there is a whole 'other' community there, as in people that we don't see here and in the Projects. Flowers to you all on this page.
Actually, you don't need to download the design to comment on it, for example the letters of the alphabet. Just click on the letter, and scroll down to the bottom of the page, there's a box that says "leave a comment" or something like that. Sometimes you have to go down pretty far, if people have left lots of comments, it's at the bottom of the page.
Just click on the link next to the picture of the project and you'll be able to leave your comment on that specific project. If you want to comment on one of the free designs, after you download it just scroll down to the bottom of the page and you'll see a comment box. Hope this helps...good luck!