The latest book by the former Wall Street trader and now financial commentator Michael Lewis is called Flas Boys.
[http://www.play.com/Books/Books/4-/60801888/Flash-Boys/Product.html?searchstring=Flash+Boys&searchsource=0&searchtype=allproducts&urlrefer=search]

Without spoiling the book, it is about the growth in High Frequency Traders (Robots). The book revolves are the good guy Brad Katsuyama, a  trader at the RBC (Royal Bank of Canada), who worked out that the high-frequency guys were effectively hijacking his orders by effectively front running his orders. Using low latency high speed fibre-optic cables that link superfast computer servers to brokers, these high frequency traders intercepted and bought his orders, selling the shares back to him at a higher price, and pocketing the margin. Thus an decent trader is unable to get best prices.

The effect of this is most serious, as long term investors like pension funds unable to get best prices for clients, when you have High Frequency Traders just in the market for micro seconds to make a margin. One has to really ask the economic benefit of a robot owning a share or bonds for a few micro seconds.