Spotify - Map shows when two people play same song at same time
Attendify - Develop relationships at the events that you attend by creating smaller events with just a few people.
SoundCloud - Enjoy music & follow favourite artists
CrowdCompass - CrowdCompass offers mobile app development for conferences, meetings, conventions.
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
EventMobi - EventMobi is an interactive mobile event app, audience response and engagement platform for conferences and trade shows.