I think there's a good case to be made for security as an exercise in public health. It sounds weird at first, but the parallels are fascinating and deep and instructive.
Last year, when I finished that talk in Seattle, a talk about all the ways that insecure computers put us all at risk, a woman in the audience put up her hand and said, "Well, you've scared the hell out of me. Now what do I do? How do I make my computers secure?"
And I had to answer: "You can't. No one of us can. I was a systems administrator 15 years ago. That means that I'm barely qualified to plug in a WiFi router today. I can't make my devices secure and neither can you. Not when our governments are buying up information about flaws in our computers and weaponising them as part of their crime-fighting and anti-terrorism strategies. Not when it is illegal to tell people if there are flaws in their computers, where such a disclosure might compromise someone's anti-copying strategy.
But: If I had just stood here and spent an hour telling you about water-borne parasites; if I had told you about how inadequate water-treatment would put you and everyone you love at risk of horrifying illness and terrible, painful death; if I had explained that our very civilisation was at risk because the intelligence services were pursuing a strategy of keeping information about pathogens secret so they can weaponise them, knowing that no one is working on a cure; you would not ask me 'How can I purify the water coming out of my tap?'"
Because when it comes to public health, individual action only gets you so far. It doesn't matter how good your water is, if your neighbour's water gives him cholera, there's a good chance you'll get cholera, too. And even if you stay healthy, you're not going to have a very good time of it when everyone else in your country is striken and has taken to their beds.
If you discovered that your government was hoarding information about water-borne parasites instead of trying to eradicate them; if you discovered that they were more interested in weaponising typhus than they were in curing it, you would demand that your government treat your water-supply with the gravitas and seriousness that it is due.