Not hoping to start any sort of flame war, but could someone try to explain this difference between streams and promises? The conceptual difference doesn't seem completely clear to me.
Streams are a totally different use case. Streams are used when you want to process data one part at a time without having to have all of the data in memory at once.
*edit: typo
With a promise (or rather, following the promise specification) you instead get back an object that you choose how to handle. That object is either pending or else an immutable success or failure result. Either success or failure will be called (not both), and whichever result is called can only be called once. As such, promises allow you to avoid inversion of control and to safely interact with potentially untrusted code.
This great series of articles helped me understand this: http://blog.getify.com/promises-part-2/
A queue of promises would be similar to a stream.