From Wikipedia; RSS (RDF Site Summary or Really Simple Syndication) is a web feed that allows users and applications to access updates to websites in a standardized, computer-readable format. These feeds can, for example, allow a user to keep track of many different websites in a single news aggregator. The news aggregator will automatically check the RSS feed for new content, allowing the list to be automatically passed from website to website or from website to user. This passing of content is called web syndication. Websites usually use RSS feeds to publish frequently updated information, such as blog entries, news headlines, or episodes of audio and video series. RSS is also used to distribute podcasts. An RSS document (called “feed”, “web feed”, or “channel”) includes full or summarized text, and metadata, like publishing date and author’s name.
What it really is, is your connection to the world for your podcast. The transmitter for your “Radio Station”. Your RSS feed address is just like a “Frequency” Like “101.9 FM”.