Social messaging app Snapchat has been a bit of a phenomenon since its launch back in 2011. It's all about being able to send picture and video messages which expire once they have been viewed a single time. Initally this made them very popular as a way of sending nudie pics. Because young people.
Lately Snapchat has gone more mainstream, with upwards of 700 million photos and videos being sent each day - as well as the company finally making sure that everything gets deleted from their servers. And the app is getting added functionality today - now you can play music from your handset while recording a video. Previously you had to play audio out of another source and hope that it didn't sound too terrible but now you can just have another app open - your music player, Spotify, etc - and it'll sound great in the app.
You still can't do any live editing, which means you'll have to do some work if you're looking for things to sync up nicely, but its definitely something users are going to enjoy. And we're presuming the inpermanent nature of Snapchat messaging means that copywright isn't an issue.
This update is live now for iPhone users only, hopefully it rolls out to Android soon enough.