What's with the little tape reels?

[andychamp]

Y'know, next to the thread titles?
White, yellow, turning, static...
So far I know: a little red dot on the left means that I've posted in that thread.
Also: what are the red pages that appear on some threads next to the reel?
Hope this is the right place to ask, thanks.

[transmothra]

white = read topic
yellow = unread topic
spinning = hot topic
static = lukewarm topic?
red light = you've posted in that thread