For non-geeks, I would drop the word "intelligence", which carries too much baggage.

"Machines that can improve their ability to improve themselves can improve very quickly -- much faster than you might expect if you don't look at the math. And if a machine quickly self-improves to the point where it can change the world in radical ways, those changes might make us really unhappy or even kill us all. So we want self-improving machines to be 'Friendly' -- that is, we want them to be designed in such a way that the changes they make to themselves and their environment are good for humans. The upside is that a Friendly self-improving machine can also make the environment much, much, much better than you might expect... for example, it can develop improved technologies, cures for diseases, more reliable economic models, extend longevity, etc."

Come to think of it, that might be better for many geeks as well, who are not immune to the baggage of "intelligence". Though many would likely be offended by my saying so.

Yes - and geeks are not representative of the population at large, and not at all representative of powerful individuals (politicians, government officials, army commanders, rich businessmen). Even with geeks, I expect a success rate well below 100% due to future shock and imperfect updating.