The Economist story that reports this development contains these factoids:
- Algorithmic trading accounts for a third of all share trades in America
- The Aite Group reckons it will make up more than half the share volumes and a fifth of options trades by 2010
- The new London Stock Exchange system catering to the growth of algorithmic trading cuts trading times down to ten milliseconds; on its first day, it processed up to 1,500 orders a second, compared with 600 using its previous system
Taken a step further, I can imagine the trading houses selling re-tagged news feeds back to Dow Jones and Reuters. Suitably anonimized, aggregated, and delayed to protect the individual movers, information on which news items triggered trades would be useful at second order. And then the news providers can sell the re-re-tagged feeds to the traders, who'll then sell back the re-re-re-tagged . . .