I always see the press as doing a very good job in hindsight reporting, which sometimes helps to push sentiment to extremes an takes prices along with it. I guess you could call it a feedback loop where the more the news goes round the more negative the market becomes. Have a look at this link to Reuters news on 15th October 2014;
http://www.reuters.com/article/2014/10/16/us-markets-global-idUSKCN0I402B20141016
Does it sound very close to Friday's news?
http://www.reuters.com/article/2015/08/21/us-markets-stocks-usa-idUSKCN0QQ15Y20150821
On Friday all methods that I use to gain a direction were pointing to a reversal which did not occur. In fact another day like Friday would by my measurements put us very close to the financial crisis levels that occurred 2 days before a huge reversal.
Friday was also a huge volume day. The last time we saw volume this large was 15th October 2014 and so no need to explain what came after that.
Of note is that markets tend not to rally when everyone is bullish and tend not to decline when everyone is bearish. One thing for certain is that the volatility is greatly appreciated. Tomorrow could make for another exciting day.