Ignore the green curve for a second. The gold curve is the 'bid' curve. It shows, at any given USD value (horizontal axis), how many Bitcoins people are willing to buy (vertical axis). So it says that, based on the orders currently in the market's books, at the $6.00/Bitcoin price point, you could sell up to 23,282 Bitcoins to get $549,907. This trade could happen immediately, because the matching buy orders already exist.
Similarly, the blue curve is the 'ask' curve. It shows how many Bitcoins people are currently willing to sell at any given price. So right now, at the $8.00/Bitcoin price point, you could buy 19,242 Bitcoins at a cost of $144,682.
Obviously, you'd be stupid to do either of those trades because they're far from the market rate. The action happens where those curves meet, currently at $7.10362-7.18242. This means that, currently, someone could buy at least one Bitcoin at $7.18242, or sell one at $7.10362. If someone were to put either a buy or sell order in between those numbers, then it would sit there until a match came in.
Which brings us to the green curve. This is the trade history. Like the other curves, the horizontal axis is the price, but here the vertical axis is time. It shows, trade by trade, what prices Bitcoins have actually traded at. Right now, the most recent is $7.10110; this is what people quote as the market price.
Ignore the green curve for a second. The gold curve is the 'bid' curve. It shows, at any given USD value (horizontal axis), how many Bitcoins people are willing to buy (vertical axis). So it says that, based on the orders currently in the market's books, at the $6.00/Bitcoin price point, you could sell up to 23,282 Bitcoins to get $549,907. This trade could happen immediately, because the matching buy orders already exist.
Similarly, the blue curve is the 'ask' curve. It shows how many Bitcoins people are currently willing to sell at any given price. So right now, at the $8.00/Bitcoin price point, you could buy 19,242 Bitcoins at a cost of $144,682.
Obviously, you'd be stupid to do either of those trades because they're far from the market rate. The action happens where those curves meet, currently at $7.10362-7.18242. This means that, currently, someone could buy at least one Bitcoin at $7.18242, or sell one at $7.10362. If someone were to put either a buy or sell order in between those numbers, then it would sit there until a match came in.
Which brings us to the green curve. This is the trade history. Like the other curves, the horizontal axis is the price, but here the vertical axis is time. It shows, trade by trade, what prices Bitcoins have actually traded at. Right now, the most recent is $7.10110; this is what people quote as the market price.