• Eilish's "Bad Guy" ended the record 19-week reign of Lil Nas X's "Old Town Road" at the top of the Billboard Hot 100 this week, making her the first artist born in the 2000s to hit #1 on the chart.
• If Eilish hadn't succeeded, "Bad Guy" would have spent a record-tying 10 weeks at #2 without ascending to the top spot.

The big picture: Streaming is already the biggest factor for Billboard's charts. Last year, it changed how streams count toward the Hot 100, granting the most weight to songs played under paid subscriptions with services like Spotify and Apple Music.

And on-demand songs from ad-supported services (think YouTube and streaming services' free tiers) have more weight than songs played on programmed services, like Pandora.

• 84% of Gen Zers use their smartphones to consume audio content daily, according to a Consumer Technology Association survey. It also found that their two most popular sources of audio content were streaming services and online video.
• A Music Business Association survey found that 15- to 19-year-olds are far more likely to opt for paid streaming than other age groups because of their preference for mobile streaming — even though 24% said they weren't the ones paying for it.

Eilish and Lil Nas X fought a months-long battle for #1, targeting their peers across their preferred platforms the whole time.

• "Old Town Road" first entered the chart at #83 in March, thanks to its plays in memes on TikTok, Gen Z's social platform du jour.
• Lil Nas X released a slew of remixes — adding artists like Billy Ray Cyrus, Diplo, Young Thug and RM of BTS — to keep his song safe at the top with continued buzz. Eilish tried to deny his record stay at #1 by enlisting Justin Bieber for a "Bad Guy" remix last month, but that effort failed.
• Both used delayed music video releases to pique interest. "Old Town Road" saw its cameo-filled video drop in May — months after the song's initial release to guarantee tens of millions of new streams. And a mobile-centric alternate vertical video for "Bad Guy" came out just last week, a move that likely helped propel the song to #1.

The bottom line: The world's biggest record labels have already caught on — and soon, these promotional strategies won't be limited strictly to the young.

Go deeper: Taylor Swift unloads on Scooter Braun's Big Machine deal

Swift also told the magazine she believed her own personal controversies at the time, stemming from her feud with rapper Kanye West — who later famously declared his support for Trump — wouldn't have helped Clinton:

"Also, you know, the summer before that election, all people were saying was 'She’s calculated. She’s manipulative. She’s not what she seems. She’s a snake. She’s a liar.' These are the same exact insults people were hurling at Hillary. Would I be an endorsement or would I be a liability? 'Look, snakes of a feather flock together. Look, the two lying women. The two nasty women.' Literally millions of people were telling me to disappear. So I disappeared. In many senses."

The big picture: Since her 2018 endorsements, Swift has become much more vocal about her political leanings — especially on LGBTQ issues. She wrote an open letter in June to Tennessee Sen. Lamar Alexander, a Republican, asking him to support the House-passed Equality Act.

• Her Change.org petition on the subject has been signed by multiple 2020 Democratic presidential candidates, including Elizabeth Warren, Cory Booker, Beto O'Rourke and Amy Klobuchar.

What's next: Swift will likely increase her political activism heading into 2020. She told Elle earlier this year, "Invoking racism and provoking fear through thinly veiled messaging is not what I want from our leaders, and I realized that it actually is my responsibility to use my influence against that disgusting rhetoric."

• "Only as someone approaching 30 did I feel informed enough to speak about [politics] to my 114 million followers. ... I’m going to do more to help. We have a big race coming up next year."

Go deeper: Celebs largely shun 2020 spotlight

• Elon Musk started Neuralink, which wants to create a machine that can directly interface with the human brain, to stave off what he sees as the existential threat of artificial intelligence. And his billion-dollar Boring Company wants to solve a much more mundane nuisance with urban tunnels: traffic.
• Bill Gates has sunk $500 million of his own wealth into nuclear power startup TerraPower as part of his push against climate change, per Axios' Amy Harder.
• Jeff Bezos and Musk believe that humanity's future lies in space, pouring millions into Blue Origin and SpaceX to bring people to orbit, the Moon and beyond.

The state of play: While details on Kanye's ultimate plan for his housing concept remain sparse, he told Forbes' Zach O'Malley Greenburg earlier this month that the domes "could be used as living spaces for the homeless, perhaps sunk into the ground with light filtering in through the top."

• Greenburg also notes that the structures were "inspired by Luke Skywalker's childhood home" on the planet of Tatooine from "Star Wars."

The state of play: While Kanye might be viewed as something of a dilettante — often jumping between music, fashion and design — he's had his eye on the architecture space for over a year.

• He tweeted last May that his new architecture arm, called Yeezy Home, was "looking for architects and industrial designers who want to make the world better."
• His Yeezy Home collaborators posted concept renderings of a low-income housing space on Instagram which were later deleted, per The Architect's Newspaper, though its spartan concrete design doesn't seem to reflect the current dome concept.
• And he told radio host Charlamagne Tha God last year that he wants "to be one of the biggest real-estate developers of all time" while the two toured the Calabasas property on which the domes would ultimately be built.

"We're standing on my first property. I’m going to be one of the biggest real-estate developers of all time, what Howard Hughes was to aircrafts and what Henry Ford was to cars — just the relationships I have with architects, my understanding of space and sacred proportions, Just this new vibe, this new energy. We're gonna develop cities."

The other side: Experts doubt that Kanye's project could ever actually scale to make a dent in Los Angeles' housing problem. "You would need to build 100,000 of these every year for the next 10 years to scratch the housing backlog," Tyler Drew, president of Anubis Properties Inc., told Realtor.com.

• He also cited the city's zoning laws and its activist, "not-in-my-backyard" population as roadblocks to ever seriously expand Kanye's affordable housing concept.
• Such zoning restrictions, which disproportionately impact low-income residents and people of color, limit cities from getting denser and are often the primary drivers of exploding housing costs in booming cities, as Axios' Erica Pandey reported.

Go deeper: The state of affordable housing in Los Angeles