Apple made a dig at Spotify during its big event and Spotify's CEO was not thrilled
So what was it?
When Apple debuted its new music streaming service, Taylor Swift was in the #1 spot on the video charts.
Taylor Swift famously does not get along with Spotify. She argues that its free, ad-supported model fails to properly value artists' work, and removed all her most recent music from the platform after a high-profile falling out.
Shortly after she pulled her music from Spotify, her album 1989 sold 1.3 million copies within its first week - the most of any album since 2002 - and became the top selling album of 2014.
Apple Music, which will not have a free tier, does have Taylor Swift's music - and the company not-so-subtly showed that off on stage.
What does Spotify have to say about all this? Spotify CEO Daniel Ek sub-tweeted to acknowledge he caught the dig, then deleted it.
(Sub-tweeting is when you make a comment on Twitter that's obviously in reference to something, but you don't actually state the original the reference).
Here's what Ek tweeted: