I have a question. I see on that page the following URL:

  https://groups.google.com/forum/#!forum/chrome-notebook-pilot

Recently I see the characters '#!' more often used in URLs. Why? What's the reason behind it? I know that a # in an URL denotes the 'fragment', but what's the advantage of using it in this case? The page to which the URL refers to doesn't even need the browser scroll to a certain part.