That's been going on since the late 1970s, when personal computers first became available. It worked back then, because few were doing algorithmic trading at the time. Now, everybody is.
There's new interest in systems which look at external data sources such as news items, rather than just at market data.[1] They have a chance of picking up something before the market reacts. But that's already widely deployed; about 15% of HFT operations were using it by 2013.[2]
Algorithmic trading is more than just HFT, where every microsecond counts, and where these small-scale day traders cannot compete.
Your example of analysing new items is a good one. If you can spot a better way to predict stock or currency movements by a cunning new way of processing news feeds, then you could potentially profit from it without having to rely on speed of execution.
People have been using computers to do stock analysis, as you say. But this doesn't make it a solved problem. There's money to be made if you can do it better than the others. Of course, the competition is very tough.
There's new interest in systems which look at external data sources such as news items, rather than just at market data.[1] They have a chance of picking up something before the market reacts. But that's already widely deployed; about 15% of HFT operations were using it by 2013.[2]
[1] http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2326414 [2] http://www.automatedtrader.net/online-exclusive/67056/fit-to...