"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Confirms HomePod's Supported Audio Sources in Tech Specs
• iTunes Music: HomePod users can ask Siri to play any songs, albums, or audiobooks purchased from the iTunes Store.
• iCloud Music Library: HomePod users can ask Siri to play any songs uploaded to a user's iCloud Music Library, including songs imported from other sources such as CDs, with an Apple Music or iTunes Match subscription.
• Beats 1: HomePod users can ask Siri to play Apple's official radio station.
• Podcasts: HomePod users can ask Siri to play any podcast episodes from the iTunes podcast directory.
• AirPlay: HomePod users can use AirPlay to play other audio from an iPhone, iPad, iPod touch, Apple TV, and Mac. AirPlay 2, coming later this year, is only required to stream audio from these sources to multiple HomePods.
Earlier this week, iMore's Serenity Caldwell put together a useful breakdown with more detailed information about how the HomePod works with Apple Music, iTunes Match, iCloud Music Library, AirPlay, and more.
HomePod orders began last week ahead of the speaker's official launch on February 9 in the United States, United Kingdom, and Australia.