I think the green arrow means that I have posted to the thread and not that it contains new content. The envelope thingie is open with multiple pieces of paper sticking out of it for new content. See the bottom of that page listing topics for a definition of the icons ;-) In the meantime, I find the What's New tab at the top of the page is helpful.And re. new posts, we just need to get used to looking for the little arrow next to the thread's name instead of the color of the icon.