Google Music All Access Discount
Google Music announced their All Access service at IO. They also announced a $2 discount to those who sign up for the beta trial before the end of June.
I have a feeling Google can offer a discount to its customers because it already offers streaming of owned-and-uploaded music. Remember, before All-Access, Google Music was a locker storage service. You upload music you "own" and they stream it back to you, for free!
They have to pay royalties to artists for streaming of music in their radio service (because it is considered a public performance just like normal radio/Spotify/etc), but if you own a piece of music and you just move the bits around from here to there, you have already paid the fees upon the original "purchase". Since they will stream your owned music back to you instead of their all-access service when it is something you already uploaded (note how "my library" tracks show up first in results when you search for an artist) they don't have to pay - and if you have a large enough library on google music, perhaps this is large enough to warrant a $2 discount per month. I'd imagine they think those paying attention to IO and signing up for the beta this early are likely already using the service and have uploaded massive amounts of music.