Allihoopa
So some of you know that I'm a big fan of making music with my iPad and iPhone. One of my favorite apps is Figure, by Propellerheads; it's an incredibly easy-to-use and intuitive tool for making quick, small pieces of music. Great for sketching or just jamming out with.
A while ago, Propellerheads started a site called Propellerheads Discover, which was designed around uploading Figure, Take, and Reason tracks to their own little version of a social network. You could then download project files from artists you followed, remix and build on them, and then upload them again.
Just today they rebranded Discover as Allihoopa. For the past week or so I've been adding some of my Figure sketches and doodles (including an Undertale track I built of of one of @rnn's projects) to the site. Check it out and follow me, and if you're also uploading stuff to Allihoopa, post your profile here so people can follow you.