Anyone with an interest in how algorithmic trading is able to artificially control prices should check out the case studies made available on the following link.
Copy and past the link in a new browser. (Sorry, I am not sure how to make it do that automatically)
The website shows how market manipulation takes place with full regulatory approval. I put the link on the PLS thread yesterday, but here is probably a good spot for it too. At long last some of the mysteries and the rorts that result from computerized markets are being exposed.