I love the way you show the way the code is supposed to be used before implementing it, I'm going to steal that
the Pledge class is great, it helps clarify promises for me
the note about .bind is great
I also love "How are real promises different?"
I didn't really understand why the character encoding example uses promises (instead of doing a synchronous read). This is a confusion I have in general with Node though -- I often see code that uses promises for reasons that are unclear to me.
re "What is the difference between setImmediate and process.nextTick? When would you use each one?" in the exercises -- it wasn't clear to me how I was supposed to figure out the answer to this question. I Googled it and found a pretty good blog post.
.bindis great