Comcast's NBC is airing both the Super Bowl and the Olympics in February, a double-whammy sports extravaganza that the company expects to yield $1.4 billion in ad sales. That would help justify the hefty price it's paying for both events.

NBC is banking on these sports events since traditional TV ratings have slumped in recent years. Live sports are marquee TV events that draw most of the largest TV audiences, but even those ratings have declined. More Americans are dumping their cable packages and advertisers are following consumers to their phones.

Spending on U.S. TV ads is expected to grow an anemic 0.4 percent this year, according to eMarketer.

So NBC is continuing some digital efforts from Rio and expanding others to meet viewers wherever they are.