Google’s Play Music service previously required installing the Music Manager app to upload music to the cloud service on Mac, Windows, and Linux. Today that changes as Google adds the ability to drag-and-drop your music collection to upload it directly through the browser within the Google Play Music web interface. It’s still in “lab” beta mode, but you can easily enable it:
To add new music, enable the “Google Play Music for Chrome” lab atplay.google.com/music/listen#/labs. Then simply drag and drop songs into your Google Play Music library. If you have a lot of music in iTunes or if you want new music to be added automatically, you can configure this by clicking “Add Music” at the top right of play.google.com/music.
Also new for the Google Play Music web app is downloads for offline listening and a new mini-player that you can pop out using the arrow in the bottom right corner of the UI.