Public sharing means that anyone can listen to your playlist, and it will show up on your SoundCloud profile page and your followers’ Streams. Private sharing is exclusive, giving you control over who has access to your playlist and who doesn't. Private playlists won't show up on your public profile and can't be searched for within SoundCloud.
To change the sharing settings of your playlist, go to the Basic Info tab of the edit page and select either private or public.
Please note: If your playlist is public, but the tracks within it are private, any listener that is not logged into your account will not be able to view these tracks. To have these tracks visible, make the playlist private and share its secret link with select recipients.