Kevin Schroeder has another new post to his blog today with an excerpt from his "You Want to Do WHAT with PHP?" book. This new post is a section from the fourth chapter looking at stream handling.

Communication is key to building applications now and for the future. While it is not something that I think that everyone should do, I have not seem many applications that make good use of streams in PHP. Streams can be immensely useful in the right situations, but a lot of developers are not really aware of how streams can be used. [...] While I don't think you will end up basing your application around streams it is a really good idea to know how streams work.

The sample code (and description) talk about changing the properties of a stream on the fly. He shows how, with a fgets loop checking the input, he can catch a command from the already running script and change the compression setting on the currently open stream. The compression changes the stream's data from plain text to a binary format as handled by the streams functionality.