Before the opening bell some pundits were muttering about carnage on Wall Street. But clients of iSentium — about a dozen hedge funds — were urged to be bold. According to the Twitter-mining machines built by the New York-based company, the S&P 500 index was set for a rebound on the morning of August 24, once the opening skirmishes were out of the way. The software had examined the language of hundreds of thousands of stock-related tweets and predicted that the prevailing mood in the market that day would be more positive than negative. Hence the recommendation that investors buy the SPDR S&P 500, an ex­change-traded fund that tracks the index.

http://www.ft.com/intl/cms/s/2/99a7e7ec-4fea-11e5-8642-453585f2cfcd.html#axzz3kdJxULnZ