It looks like DARPA deactivated the Grand Challenge discussion forum a while back, hence the lack of new posts in the feed. I'll keep the feed URL going for a bit, but it too will eventually disappear.
Until next time,
DARPA's Grand Challenge discussion forum doesn't have an RSS or Atom feed, which makes it painful to keep up on the latest posts. My solution is to scrape the site and offer a feed here.
This feed is updated every half hour and contains the 100 most recent posts to the forum:
If you're hardcore, this feed contains every single post ever made to the forum, and
is approximately 1 MB in size (it is also updated every half hour):
John Wiseman <firstname.lastname@example.org>