RSS (Really Simple Syndication) is a format for syndicating news.
This symbol ( or , it's the same thing) helps you subscribe to this publication through a special browser like RSS Reader or Pluck.
It's also easy to subscribe from within My Yahoo (turn on RSS Headlines).
To subscribe , just right-click on the symbol, select Copy Shortcut, then open your RSS Reader - the link will show up in your Add A Channel window. Try it!
Open Pluck using the new icon on your IE toolbar (this is cool).
You can drag an button into a Pluck RSS folder to subscribe to the feed. (more)