Rideau Park uses RSS (Really Simple Syndication) feeds, which allow you to be notified of certain types of new content on this site, without having to visit the site yourself. You can then read and/or listen to that content at your convenience.
A page on which the 
symbol appears contains an RSS feed. Right-clicking on the symbol and selecting “Copy Shortcut” or “Copy Link Location” (depending on your browser type) will copy the feed information to the clipboard. It can then be pasted into your favourite RSS Aggregator or Reader (one such program is Awasu*).
* This program has been tested with Rideau Park feeds, but no other endorsement of it should be inferred.