Eddy said tonight that Apple has been thinking about subscription music for a long time.
Not sure why they had to think about it for a long time. I've been streaming music on various services for years -- many years if we're counting Pandora. Apple could've started streaming their entire iTunes catalog and charging me $25 a month to stream as much as I wanted and I would've gladly paid that a year or two ago.
However, I'm now paying Spotify $5 a month for unlimited streaming on my Mac. I'm quite confident that Apple won't be willing to come close to that price so they had better offer a compelling reason for me to switch to their offering when it arrives and pay more. And no, Siri integration on the phone and "mood" playlists are not good enough reasons for me, personally, to switch.