If you're looking to make the argument that soccer has finally gained a foothold with the American sports-watching public, you'd be off to a good start by citing the TV ratings from last night's thriller between Portugal and the United States, because they were bananas.
According to Sports Illustrated's Richard Deitsch, ESPN's broadcast of the game averaged 18.22 million viewers, while Univision brought in another 6.5 million. That's the most viewers either network has ever had for a soccer match involving an American team, and as Deitsch points out, the actual number of viewers is likely a fair bit higher due to how many people watched the game at various viewing parties. Here's a jarring sentence:
The match was ESPN's most-viewed sporting event on its airwaves excluding NFL and college football telecasts and is a clear indication of the growth of the World Cup as a television event.
For comparison's sake, Game 7 of the 2013 NBA finals averaged 26.3 million viewers, and as Joe Posnanski pointed out, only one World Series game in the last decade—Game 7 in 2011, if you're curious—has done as well. So yeah, a lot of people are watching soccer. Sorry, Dan Shaughnessy.