My fingers are really good at Alt-Tabbing, but my brain isn't. My questions and concerns need to be answered on the spot when I'm taking a MOOC, simply because that is the quickest and most effective way to learn. Most of the questions are answered through the forum, so we made that accessible while watching course lectures. I also watch all my videos at 2x speed to save time. Sometimes 2x isn't enough, so we increased the range and variety of playback, along with some Spritz functionality so I can better absorb the content at faster speeds. We are using NLP to query the forums to bring you relevant forum discussions when you are confused.
There are plenty of features to implement. We want to have better subtitle to speech syncing (it can probably be done better natively). I know this will make my own Coursera experience a whole lot better.