As Seth Stevenson noted four years ago, marketers for car insurance can sell to most of the American populace. Nearly everyone needs car insurance. The market's huge and fragmented, so marketers put ads everywhere.

I live in New York City, where many adults do not own cars. However, most of us do own cell phones. It's a safer bet that any random person I meet at a party will have a cell phone than that she has attended college. Cell phone and telecom ads proliferate on the subway.

When I'm making small talk at a party (second bullet point), or with a person sitting next to me on the bus, at some point someone's phone will make an appearance. Someone checks the time, or silences a call, or checks Wikipedia or IMDB. And you can make a good three minutes of small talk with that. "Oh, how do you like that phone? Do you get good reception? I don't have a smartphone, I'm deciding what to get. So hard to decide, choosing a phone and a carrier and a monthly plan..." and everyone has an opinion. It's the new weather.