envelopes: just a picture, could be anything
inward arrow: you've posted in this thread
outgoing arrow: thread has been moved to another section
red envelope: hot topic
green dots: next to username==> user is online/ grey dot: user is offline
green squares: reputation users got. (luvfriday is an unknown quantity at this point) because you're just registerd and don't have much reputation yet, it will grow believe me)