I just saw this tweet with the above picture:

https://twitter.com/zhusu/status/1072633621108940801?s=21

- zhusu

It suggest a very large drop off of money and users from bitmex happened very recently.

In fact this drop is so significant it may well be one of the forces pushing prices lower (as volume reduces price will fall)

So I am looking for an explanation of what happened here.

Update: My own conclusion

I am not that impressed with the answers so far.

I saw this when I was on the road, when I came home the first thing I did was look at the real volume vs the order above.

The thing is that the order book increased inversely to the reduction of volatility and return back to a little higher level of high volatility when the price broke out. Thus we have slightly higher order book now than a year ago. Both times we had high volatility.

Volume overall has increased since the drop.

Many people may have exited the market but the traders are still here!

That said we may have seen a slight reduction of volume overall, as many many people are leaving the bitcoin.