Davey Shafik has gotten more than a little excited by the streams functionality in his latest blog post:

PHP streams are absolutely amazing. As mentioned by Elizabeth Smith (a great read if you don't know how to use streams) PHP streams are super powerful. Streams is something that is (to my knowledge) unique to PHP. The closest thing I've seen to it, is Linux's FUSE "user space" (i.e. not kernel module) file systems.

He shows an example of a stream in action and suggests an interface he'd like to see - an automatic connection to the Amazon S3 storage.