RSS or Really Simple Syndication is an easy way to keep you automatically informed of your favorite websites or other sources. You do not have to surf to these sources to see if the pages have been changed. You can subscribe to RSS feeds from your favorite sources and then get automatically a message by RSS when web pages are updated. Similar to the message that you have new e-mail. RSS feeds are recognisable by this icon
How to subscribe to a feed?
To view RSS feeds you need an RSS reader which you can freely download from the Internet. Examples: FeedReader (desktop reader), Feedly (webbased reader), …
A comprehensive list can be found at http://en.wikipedia.org/wiki/Comparison_of_feed_aggregators
The current major browsers like Internet Explorer, Google Chrome, Safari, Firefox and Opera also support RSS.