A recent New York Times article reveals that window watching (spying on your neighbors) is a common activity in big cities, where apartment windows often face each other. One woman interviewed for the article notes, "In a large city where there’s a lot going on around you, it can feel very isolating and lonely. By having contact with these total strangers through the window, it’s a safe way of having a relationship without the hard part of a relationship."
While I don't live within window-watching proximity, I know that many of my friends have sneaked in a little window watching in the past. What about you?