The idea of stock should be simple really, but it’s scary, because on MSNBC, there’s this rolling ticker with hundreds of stocks on it, and they show all these graphs and talk about opening and closing prices. It’s hard to imagine that Facebook—something that I use every day to look at pictures of my friend and other people I don’t know yet—can be worth some amount one day, and then the next day, it’s worth some wildly different amount.