I posted an early version of this side project 3 months ago and got some good feedback so I thought I'd post it again with the new features.
MisterJack is a tool to easily make a playlist from a few tracks (streamed from Youtube & Soundcloud).
Playlists are saved online and become collaborative if you share the link with your friends. There are also suggestions of tracks to add to your playlists if you're low on inspiration. These suggestions are also played if your playlist reaches the end.
More features will be added with time (accounts, private non-collaborative playlists, playlist forks, etc.).
A lot of time and work went into making this rather simple product and it has been an immense pleasure building it on my own (and learning many things on the way).
I hope you enjoy it :)