I don't think there is any place that tells you what all the colors and icons mean.
Here are the ones I do know. :wink:
"i" in a circle = Announcement(generally made by a mod or Alex)
"light bulb" = sticky thread
Red circle = new posts
Blue circle = no new posts
If the lines are moving in the circle it has 10 or more replies
"*" on the icon means it's a topic you've posted in
"padlock" symbol = topic/thread locked
There are probably more, I just cannot remember what they are :roll: