The graph is tough to read as is. There's no labels for the x data and they y is autoranged. As of 1020 Eastern US time today, all I see are two horizontal lines. So I can see that both the Tether/Bitfinex/Bittrex/Poloniex cluster and the USD/Bitstamp/Kraken clusters are stable. But without an x label I can't tell if they're stable over the last hour, month, or year.

* If I mouse-over the x ticks, I can see that the graph spans ~10 minutes, but most people probably wouldn't have the patience. Now that I know it's been stable for ten minutes (is it usually unstable across ten minutes‽), my next question is 'how did it look over the last 30 days? 12 months? *

All in all, a cool site! Just a tip from the graph-nitpickers out here.

EDIT: I see now, this graph shows only current activity since page load. This was likely a tradeoff to simplify the design of the page such that the data didn't have to be stored on the server. Maybe the page is such that the data is requested directly from the exchanges themselves?