Starting in the first quarter of next year, the company will reward binge watchers of its programming, presenting an ad-free episode after they’ve watched three previous ones in a row.

It’s an enticement that could keep viewers around for longer periods—and could nudge them toward paying more per month for an ad-free plan. And it’s one of a series of upgrades for ad-supported customers.

The video quality of programs under the membership tier is being increased from 720p to 1080p, and members will be able to download films and series by the end of the week. Netflix says this makes it the only ad-supported streaming program to allow downloads.

Members are now also able to stream two programs concurrently.

The upgrades come as subscriptions to the ad tier have hit 15 million people globally, a big surge for a company that once swore it would never embrace advertising in its programming.

For companies looking to access that audience, Netflix is rolling out new ad units, which can run 10, 20 or 60 seconds, beyond the 15- and 30-second ads currently offered. It’s also being a lot more liberal with the types of ads it will accept. And starting next year, advertisers will be able to include QR codes in their ads.

“We’ve expanded our category availability to include dating, enhanced financial services and pharma, and enabled additional targeting like mobile devices, more genres, time of day, and continued audience demos,” the company said in a blog post. “And…advertisers globally can target the most popular series and movies on Netflix.”