Ryan and Leslie talk emerging rules of etiquette, specifically the new rules around communication. They do some demonstrating in the minicasts.
Audio Only Version:
Episode Minicasts - Handshakes and Phonecalls
Some book recommendations, to start.
Digital Etiquette by Victoria Turk. It's short and to the point on modern communication norms, and bonus, it looks good on a desk or table, (I like it when books can do double duty as functional art.) And it looks like the US version has a very different title. While the UK version is "Digital Etiquette: Welcome to etiquette 2.0 The future of good manners," the US title is "Kill Reply All: A modern guide to online etiquette from social media to work and love."
Emily Post's Etiquette. It is still the standard and on it's 19th edition updated by her great nephew and, I think, a granddaughter.
For a snarky version, not as complete but also not as dry as the Posts', try Good Manners for People Who Sometimes Say F*ck.
Modern Etiquette Made Easy is new, as in, I've preordered it. But I found it by a source I like, so it is intriguing enough that I'll link to it here.