For Billboard, the year-old music trade publication, that was once a simple question. Its charts were based on the number of CDs, vinyl LPs or tapes that fans bought at stores. But compiling its weekly charts has only gotten more complicated with the rise of streaming formats — some free, some paid — and as record companies have found ways to game the system by including free downloads of new albums with the sale of merchandise or concert tickets.
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"Without Me" by Halsey
Subscriber Account active since. The Billboard Hot is roundly recognized as the music industry's most reliable measure of song popularity. To score a No. Mariah Carey added to that historic number when her classic holiday single, "All I Want For Christmas Is You," topped the chart for the first time since its release in Moreover, thanks to smash hits like Ariana Grande's "7 Rings" and Lil Nas X's "Old Town Road" — both of which dominated radio play and streaming numbers for an unprecedented stretch of weeks — only 17 songs claimed the chart's top spot this year. They're listed in chronological order below. It had already been No. Halsey's "Without Me" took the No. It dethroned "Thank U, Next" for the second week of the year, and after briefly dropping to No.
The Billboard charts tabulate the relative weekly popularity of songs and albums in the United States and elsewhere. The results are published in Billboard magazine. Billboard biz, the online extension of the Billboard charts, provides additional weekly charts,  as well as year-end charts. The charts can be ranked according to sales, streams, or airplay, and for main song charts such as the Hot song chart, all three data are used to compile the charts. The weekly sales and streams charts are monitored on a Friday-to-Thursday cycle since July ; previously it was on a Monday-to-Sunday cycle. Radio airplay song charts, however, follow the Monday-to-Sunday cycle previously Wednesday-to-Tuesday.