Battle on the e-Gridiron.

• Author: Griffin, Jonathan
• Position: TRENDS

In the fantasy sports world, players act as owners to draft teams that compete against each other based on the performance of real-world athletes. It all involves a bit of make-believe, but there's nothing imaginary about the number of people playing or the amount of money involved. An estimated 56.8 million North Americans will participate this year, and each will spend around $465. That's 15.3 million more fans than in 2014, according to the Fantasy Sports Trade Association.

A recent twist on traditional fantasy sports involves daily competitions in which players' teams compete not for a whole season but for just one day. These daily sites are legal, even though most forms of online gaming are not, and sports betting is illegal everywhere outside of Nevada. Why? The answer comes from a combination of federal and state laws.

The federal Professional and Amateur Sports Protection Act bans betting on sports, except through Nevada's well-known sports-wagering businesses and the sports lotteries of Delaware, Montana and Oregon. All of these were in operation before Congress passed the legislation in 1993. In theory, the law should apply to fantasy gaming, but no fantasy player has ever been challenged. Fantasy sports were exempted from the ban in...