In spite of criticism, Siri is the most popular personal digital assistant out there.

Apple wrote in a press release announcing HomePod availability that Siri is now “actively used” on over half a billion devices. Apple did not provide any hard numbers to illustrate its point so it’s unclear if by active use it means once per day, once per week or once per month.

Siri, of course, benefits from Apple’s sheer scale, multiple devices it’s available across and a multi-year lead it had back in 2011 when it launched as an iPhone 4s-exclusive feature.

Siri is currently available on these models:

  • iPhone
  • iPad
  • iPod touch
  • Mac
  • Apple Watch
  • Apple TV

Apple does not permit third-party vendors to embed Siri in their accessories for the connected home like Amazon and Google do with their respective Alexa and Google Assistant products.

Instead, Apple provides a SiriKit framework to support limited third-party functionality in very specific domains, like mobile payments, messaging, reminders and so forth.

With SiriKit for HomePod, the wireless speaker will support third-party messaging apps. This will let customers ask Siri to send a message to a friend or colleague using compatible SiriKit apps, such as WhatsApp and Viber.

Reminders, note-taking and to-do list apps like Things and Evernote will automatically work with HomePod, so Siri can set reminders, create a new list, mark items as complete or create and modify notes.

Siri is also the primary interface on HomePod so you’ll be using her to set a timer, play a podcast, check the news, sports, traffic and weather and control HomeKit-compatible smart home accessories. Apple has optimized the Siri intelligence for HomePod’s focus on music.

If you’re an Apple Music subscriber, you’ll be able your music in new ways with Siri and HomePod. Not only can she access hundreds of genres, moods and activities on Apple Music, but also learns preferences and tastes that are shared across devices through iCloud.

TUTORIAL: How to sync Siri’s brain across devices

Thanks to her deep knowledge of artists, songs, albums and more, HomePod owners will be able to ask questions like, “Hey Siri, when was this song released?” or “Hey Siri, can you play something totally different?” to change the mood.

“The team has worked to give Siri a deeper knowledge of music so that you can ask to play virtually anything from your personal favorites to the latest chart-topping releases, simply by saying ‘Hey Siri’,” said Apple’s marketing boss Phil Schiller.

HomePod features an array of six built-in microphones so that the device can hear “Hey Siri” from across the room, even when loud music is playing.

And thanks to Apple’s ongoing commitment to protecting user privacy, HomePod will only send information to Apple servers (encrypted and sent using an anonymous Siri identifier) after “Hey Siri” is recognized locally on the device.