Downloadable mobile application for users to monitor, share, and react to friends' music listening activity in real-time; downloadable mobile applications for users to compile music playlists for simultaneous listening viewing or sharing of playlists; downloadable mobile application for social interaction, music streaming integration, and personalized music recommendations; downloadable software for selecting, arranging, and sharing digital playlists with other users; downloadable software for use in the delivery, distribution and transmission of digital music in the form of digital playlists; downloadable computer software for enabling transmission, storage, sharing, collection, editing, and organizing songs and other musical files in the form of digital playlists; downloadable software featuring functionalities for sending and receiving live reactions to music activity; downloadable software for use with music streaming services to enhance user engagement and social connectivity.