This gives info on live bookmarks. While we could and may implement the orange icon its important to note our RSS feeds operate in some rather unique and dynamic ways.
Click on the RSS icon on the home page or the forum index page and get the last 15 posts on the forums as a whole. Click on the RSS feed on a particular forum and get the last 15 posts in that forum. Click on the RSS feed icon for a particular post and get the RSS feed for that post only.
To get the orange icon their has to be code in the <head> section of the code. Every page on this site shares a common header so the orange live bookmark icon would lose this customization as far as how the data appears or what type of data appears. Of course for the more customized feeds one can use the manual subscribe method described in the link above.