Well, not sure if it means much, but it's still fun to look at. As for today's action, I didn't watch any of it, but based on some buyers' comments and the trade history, it was pretty apparent it was shares being passed around. People were having trouble getting orders filled partially or even completely, yet the PPS consistently walked down all day. If it walks down, it means supply is greater than demand. If orders aren't being filled, then that's obviously not the case. No one was even bid whacking, the MMs were just passing around it.
I suppose that if real orders weren't being filled, there were few opportunities to short. That might be the correlation between the MM shuffle and low short volume.