I'm not sure why it hasn't come up, but my biggest fear is that a powerful nation will use AI for their own advantage, mostly in the form of propaganda and mass manipulation through Internet. That's at least my fear, and I think that "AI taking over" is complete bullshit. Although, if let loose, AI could even accidentally manipulate humanity into any non-positive state. We know that being easily manipulable is probably the biggest vulnerability of humans (and there's lots of history to prove that).

What comes to regulations, I think it should be required by law that AI identifies themselves as AI on the Internet discussion boards and social networks. I'm not sure how it's possible to enforce this requirement (without needing proof from everyone that you're human). Captchas are already too difficult (only bots get in these days). Popular captchas (such as Google's ReCaptcha) are also centralized, which is dangerous because it gives the captcha-owner a controlling position.