The simplest answer to, “What is RSS?”, is that it’s an XML file used to publish frequently updated information, like news items, blogs entries, or links to podcast episodes. News sites like Slashdot.org and the New York Times provide their news items in RSS format. As new news items are published, they are added to the RSS feed. Being XML-based, third-party aggregator software makes reading news items easy. With one piece of software, I can tell it to grab feeds from various sources and read the news items in one location. Web applications can also read and parse RSS files. By offering an RSS feed for my blog, another site can grab the feed and keep track of my daily life. This is one way by which a small site can provide rudimentary web services with minimal investment.
The more honest answer is that it is a group of XML standards (used to publish frequently updated information like news items or blogs) that may have little compatibility with each other. Each version release also has...