very very begginner q
That would be the weight of money (WOM). If the figure is blue (below 50%), that means that there's pressure on the back side of the book and the price should shorten. If it's showing red (above 50%), that means the pressure is on the lay side, forcing the price out. Be careful of this though. It only really becomes effective combined with good volume in the market (close to post time in a horse race). Also, skilled traders are able to spoof the market by putting large amounts on one side or the other to make it appear as if a move is imminent.