I was also just wondering about the little envelope-looking icons to the left of each post. I can see from the list what each color is supposed to represent ie: yellow envelope= new post, at which point should it change colors? I try to keep up with most if not all of the newer posts and the responses, I find myself reading the same ones repeatedly, is it that they don't change colors until there is a response? LOL, I'm learning about all kinds of stuff, and I thought I was just here for the reef information. Silly me!