Playlist Machinery - Tools that help you create & organize your Spotify playlists
Youtube-DJ - Mix YouTube songs together
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
Edjing - Discover edjing and edjing Pro, the most powerful DJ apps for music lovers! Mix on Android, Windows and iOS devices and record then share your DJ sets!
Audioship - Upload audio to YouTube or Facebook
YOU.DJ - Mix SoundCloud music and Youtube videos live in your browser.