YouTube has announced that its music service has 50m subscribers, but is there more than meets the eye in that pronouncement?

It’s a spike of nearly 20m subscribers since October, when Alphabet CEO Sundar Pichai said YouTube Music and YouTube Premium had more than 30m people using the services, including people using them on a trial basis. That’s an astounding growth rate of nearly 2m people per month, suggesting that YouTube has nearly doubled its user base in less than a year, after a rough start.

There may be a simple explanation.

More than a year ago, Google announced that its Play Music would be discontinued in favor of YouTube Music. Play Music users would have to migrate their subscriptions/purchases to YouTube Music or have their collections deleted. Play Music shut down on 12/3, less than two months after the 30m number was announced.

The sudden growth of YouTube Music may be less about that platform and more about former Google Play subscribers wanting to hang on to their playlists and purchases—and remain inside the Google ecosystem.

According to biz insiders, about 60% of YouTube’s 50m are former Google Play Music subscribers.

Spotify, which announces its numbers quarterly, had 165m premium subscribers at the end of June. The more secretive Apple Music hasn’t provided an update in two years; in June 2019 the subscriber count was more than 60m.