Maybe some panic due to Bitstamp being unavailable for many users ( me included 
) ?
Nah, it has nothing to do with Bitstamp or any other western bitcoin exchange. Current decline and somewhat unstable situation is caused by Chinese government trying to curb bitcoin trading. ) ?They continuously see Bitcoin as a danger to their own domestic financial market and fiat and way for Chinese citizens to transfer money abroad.
That is why they recently announced harsh AML/KYC procedures will take place on every major Chinese exchange from now on... There might be more anti-bitcoin laws coming.
Wasn't this the reason for the big drop about a week ago? Maybe he is talking about the smaller decline just recently, after the price was pretty stable around $900 for a day or two.
Did any new news come from China yesterday that I missed?