From the NFL press release:

Partners since 2013 through the Twitter Amplify program, the NFL and Twitter will provide free, live streaming video of Thursday Night Football without authentication to the over 800 Million registered and non-registered users worldwide on the Twitter platform on mobile phones, tablets, PCs and connected TVs.

In addition to live streaming video of NFL action, the partnership includes in-game highlights from TNF as well as pre-game Periscope broadcasts from players and teams, giving fans an immersive experience before, during and after games.

No authentication required. Still, Twitter will no doubt gain new subscribers from this deal and that seems to be the primary reason for their bid.

It will be very interesting to see how much this changes the experience of watching a game.

“This is about transforming the fan experience with football. People watch NFL games with Twitter today,” said Jack Dorsey, Twitter CEO. “Now they’ll be able to watch right on Twitter Thursday nights.”

Watching Twitter. And watching Twitter worldwide. So NFL fans throughout the world will, presumably, be able to watch Thursday Night Football with no authentication required, for free.