Two Numbers: Adele Rolling in the Deep Sales

Sadness sells.

Just ask Adele, whose moody single "Hello"—her return after a three-year seclusion—has topped the charts in more than two dozen countries. "Hello from the other side," the British soul singer wails, and while the lyric seems to address an estranged lover, it could also work as a taunt to Adele's competitors in the music industry: "Hello" is a record-setter.

The song dropped in late October and soon became the first song to reach a million digital sales in one week. In fact, it smashed a record held by rapper Flo Rida, whose single "Right Round" hit 636,000 downloads in February 2009. With first-week sales of 1,112,000, "Hello" nearly doubled that benchmark. And on party playlists and in dentists' offices nationwide, it forms a funny counterpoint to Drake's "Hotline Bling," another radio hit that takes the form of a nostalgic phone conversation.

Adele's accomplishment illustrates how the metrics for pop chart success have changed—and are still changing—in the digital age. The Billboard 200 albums chart is still around, but it's hardly the barometer for pop dominance it once was. Records like James Taylor's Before This World (2015) and Tom Petty and the Heartbreakers's Hypnotic Eye (2014) routinely hit No. 1 not because these aging stars are still the rock gods they've always been but because the CD-buying population is older and more nostalgic than ever before. Teens and 20-somethings (a substantial portion of Adele's audience) are more likely to consume music online, and chart algorithms have changed to reflect this: A year ago, Billboard began incorporating track streams and digital song sales for the first time. The magazine has also introduced a Trending 140 chart to track which songs are being shared the most on Twitter.

It also now takes fewer and fewer album sales to land in the top slot. Taylor moved under 100,000 units in his first week. A decade before, for comparison, Mariah Carey's The Emancipation of Mimi reached No. 1 with 404,000 first-week sales.

The music business hopes Adele's 25, her first new album since 2011, will do this year what Taylor Swift's 1989 did in 2014—inject huge sales into the failing industry right before the holidays. Experts predict the record could ultimately sell up to 1.8 million copies. "I'm excited about selling thousands and thousands of Adele records," a New England retailer told Rolling Stone.

So the next time Adele drunk-dials a lost acquaintance, she'll have something else to gloat about.