A slightly edited version of "AI risk - executive summary" has been published in "The Conversation", titled "Your essential guide to the rise of the intelligent machines":

The risks posed to human beings by artificial intelligence in no way resemble the popular image of the Terminator. That fictional mechanical monster is distinguished by many features – strength, armour, implacability, indestructability – but Arnie’s character lacks the one characteristic that we in the real world actually need to worry about – extreme intelligence.

Thanks again for those who helped forge the original article. You can use this link, or the Less Wrong one, depending on the audience.