Bots are computer programs that do trading without human...

Bots are computer programs that do trading without human intervention.

Try this Wikipedia article for details and also this article How to Make Money in Microseconds.

If you check out the posts under ASCI and ASX  of the Topics Index for Algorithmic Trading, you'll find that a number of HC posters are angry that Bots are being used for illegal price manipulation and that the regulators are doing nothing about it.