Pro football was the nation's most popular sport -- and the highest-grossing -- long before there was a fantasy version. But it wouldn't be nearly as popular or financially successful without it.
The reason: Fantasy fans put together a hypothetical team of real players from teams across the country, and that's changed the way people follow the sport.
It used to be that NFL fans mostly paid attention to local games, tuning into big, nationally broadcast games now and then. Now every game -- even those involving last place teams thousands of miles away -- can be crucial to a fans' fantasy team. The upshot: people are watching a lot more football, making those out-of-town games more valuable to the league than ever.