Note sure if this has been done but I just made a Yahoo Pipe (best thing Yahoo did - apart from maybe Flickr)
that takes the Arduino forums RSS feed and filters via a regex /bRe: all the replies.
I figure if you want to see replies then hit Notify.
The piple can be found here, with with all the links to RSS or what every you use.
I think it works well but if you have any problems or improvements then please let me know and I will try and sort it for you.