I don't have my own Facebook but I am aware of what happens in the network of Tina, my wife. She keeps me in the loop of things that friends and family post on her Facebook. So I see lots of pictures from people we know. Given our stage of life, it's mostly pictures of everyday family life. We see pictures of kids and pets and have a window into where people go out to eat and what they cook at home. There's also some political chatter and quite a bit of social commentary.
What is missing from these Facebook posts? Any talk about sex. It seems, unfortunately, that no one in my wife's social network is having sex. To be more precise, no one ever says anything about sex. One night my wife joked "I'm going to put on Facebook, 'Going to bed, but not going to sleep'" and we cracked up because even the slightest subtle reference to the possibility of engaging in sexual activity would breach Facebook norms (at least in her network).
I will go ahead and guess that talking about sex is not taboo in everybody's social network. Surely there are folks who air out their sexual laundry on Facebook. But for those who belong to a network where the norm is to avoid any reference to sexual activity, it would make for a good breaching experiment to post "I have the best sex life ever" or "Haven't had sex in forever" or really anything that has to do with having sex.
This post is not an awkward invitation to tell your Facebook friends about your sex life. Rather, this topic is a reminder that life is an information game, to paraphrase Erving Goffman from the introduction of The Presentation of Self in Everyday Life. We share information about ourselves but not all our information. This is part of the process of face-to-face interaction. It's also the case on Facebook--where we tell people our story but not our full story--a point effectively conveyed here by Nathan Jurgenson.