TheTradeNew.com reports on a mini-crash last month:
Shortly after 1pm on Tuesday 23 April, a tweet from the verified Twitter account of US newswire Associated Press stated explosions at the White House had injured President Obama. Within minutes, the markets had bottomed out, with the Dow Jones Industrial Average sliding 145 points, or 1%, before rebalancing pre-drop, four minutes later.
These days, even Tweets and blog posts may be polled for market sensitive content in order to inform trading strategies:
Automated news reading services scan web-based news sources and social media for breaking news relevant to markets and specific securities. This can be fed via an application program interface (API), to a trading algorithm, which may act as a circuit breaker to stop trading or accelerate participation in a certain stock depending on the news.