a little on topic: i'm generating a simple feed for "newest" here: http://mimir.pipsq.com/feed.xml (updates once every 30 minutes, i hope that is ok by ycombinator).
But it didn't appeared on Firefox's address bar as it does for all other sites.
That would only appear if you put a link on the html header of the website, but you can still use the rss link at the bottom.