I have an Amy Vanderbilt book about 'modern' etiquette. She's a descendant of Emily Post (my mother used to quote Emily Post, so there ya go)
So where's the modern version for today's etiquette in the smart phone/text world? I've only recently learned that putting a period at the end of a sentence "means" something. I still haven't figured out why people who sleep with their phone under their pillow can say they didn't get a text from their mother