When someone collects an edition of your song, they are purchasing a digital collectible (think digital vinyl) that is permanently recorded on the blockchain. This means that collectors can see and verify the history or legitimacy of each collectible. The Limited Edition digital collectible includes the media (WAV and cover image) but does not include any rights or ownership for your song. Free Editions only include the cover image.
Collectors can leave a comment that is permanently engraved on a specific timestamp of the song, which other listeners will see as they listen (think Soundcloud). Their edition of your song will also be stored in their digital wallet and displayed in their Sound profile.
You can also choose to grant collectors with specific rewards for collecting, ranging from exclusive merch and show tickets, to track stems and digital meet & greet opportunities. You can also choose to grant rewards to specifically the Golden Egg winner. It is your responsibility to deliver any rewards you specify for your release.