AJAX

This thing is so powerful that you do not even need a server running to make your own RSS Readers.

You require:
- Browser and internet connection
- HTML/JS, which uses Ajax

And Booom!!!... you have a RSS reader which can read any feed you subscribe to.

And the best part is, it is no new technology, just some workaround with JavaScript. Salute to that chap in google who would have figured this out.