Open your Facebook feed. What do you see? A photo of a close friend’s child. An automatically generated slide show commemorating six years of friendship between two acquaintances. An eerily on-target ad for something you’ve been meaning to buy. A funny video. A sad video. A recently live video. Lots of video; more video than you remember from before. A somewhat less-on-target ad. Someone you saw yesterday feeling blessed. Someone you haven’t seen in 10 years feeling worried.