Give a nontechnical overview of how they work. Provide a perspective on how effective they are at reducing some common security risks. Let's see if I can manage all of that in three Chips pages. One of the most interesting aspects of the Internet is the social structure that holds it together. Despite rumors to the contrary, nobody owns the Internet.
Nobody governs it.
Nobody passes laws that all Internet citizens must obey. True, there are some rules, but they're not imposed by the Internet per se. For instance, my employer requires that the Internet access I make using DoD equipment be for business use only. That's reasonable enough. Congress has passed rules that say it's against the law for citizens to tamper with other citizens' computers.