Although not new technology, this type of client/server type realtime interaction with the user via the browser is picking up interest again, as a means to offer a more ‘compelling user experience’ to the user.
This is interesting because I worked on a project in 1998 where we evaluated the use and prototyped AJAX type functionality for a browser-based application, but dismissed the approach as trying to hard to replicate traditional client/server type functionality in the browser. Strange how things come around back into fashion again…
Google Suggest is the best example I’ve seen recently using this approach – take a look at http://www.google.com/webhp?complete=1&hl=en