More likely, the human prepares a list of scenarios of the form of "If a news story with these keywords appears, it will affect the valuation of this company in this way, perhaps plugging these numbers from the article into some model." News story hits the wire, the program reads it and applies some simple text mining, it compares the current market prices with the expected valuation, and it sends an order to the exchange to execute the trade.

Way back in 2006, I worked at a financial software startup where one of our products (the only one that made money, actually) did exactly this. The company is defunct now - it had a bit too little focus for a small shop of a dozen or so people, and its other products weren't all that succesful - but that was one of the things that actually worked.

If you're trading manually on time-sensitive information these days, you are an idiot. Back in 2006 it was something like 80% of trades on the market are automated bots; the only people who still put a human in the loop are the rubes.

I expect they'd be getting the newswire in real time via Bloomberg or Reuters, instead of off the Internet.