Note: A 'Pro' Feature Set is required to create playlists.
A Playlist is a simply list of pointers to Wotja mix files that are in your Wotja Folder, meaning Playlists are not good for sharing (unless you also share the mix files, too). A Playlist can be played like an Album.
To share a Playlist of files you need to export it as an Album (.wotja_al file) which actually includes the mix files. You can do that via the Playlist Actions menu.