The very popular blog Wait But Why has published the first part of a two-part explanation/summary of AI risks and superintelligence, and it looks like the second part will be focused on Friendly AI. I found it very clear, reasonably thorough and appropriately urgent without signaling paranoia or fringe-ness. It may be a good article to share with interested friends.
Update: Part 2 is now here.
This is probably a mistake in the article, because the 2040 median is most likely coming from this survey (www.nickbostrom.com/papers/survey.pdf), and specifically coming from when AI experts were asked what year they could be 50% sure of human level AI coming about. For comparison, the 90% interval was 2075, which paints a very different picture.
Edit: the author has fixed the phrasing on that line