FL Studio - Image-Line's FL Studio, now on it's 12th version, is a well-known music production suite and the most popular beat processor on the market, due no doubt to its longevity. Read more about FL Studio.
Metastream - Watch streaming media with friends
GarageBand - GarageBand is a fully equipped music creation studio for Mac
Watch2Gether - Watch2Gether is an app that allows multiple people to watch the same content simultaneously and interact with each other while watching.
Cubase - Cubase is one of the world’s most powerful music creation software packages. From first idea to finished recording, Cubase helps you to make outstanding music.
StreamParty - StreamParty is a watch communiry, that allows you to watch video streams in sync with the people you care about, on multiple services.