When I look at the GDAX exchange, I see that the highest ask is 8894, and the lowest bid is 8880. What I find strange about this is how close these numbers are. Suppose I were to, right now, post a bid for 5000 - something extremely low. It would probably sit on the exchange for days or weeks. So why don't I see any such bids on the exchange?
Surely somebody in the past several weeks might have gotten the idea to post a very low bid or a very high ask. Regardless of how smart or stupid an idea that is, the point is that all it takes is one person to do it in a multi-week period, and it'll show up on the exchange.
Is it just that nobody is doing this, or is it that GDAX isn't showing all of the orders posted? Or am I misunderstanding something more fundamental?