RSS (Rich Site Summary) is a format for delivering regularly changing web content. Many news related sites populate their content as an RSS Feed to whoever wants it.
Benefits for using RSS Feeds
It allows you to easily stay informed by retrieving the latest content from the sites you are interested in. You save time by not needing to visit each site individually. You ensure your privacy, by not needing to join each site's email newsletter. The number of sites offering RSS feeds is growing rapidly.
How to read an RSS Feed?
RSS Feed Reader or News Aggregator are software to allow you to grab the RSS feeds from different sites and display them for you to read whenever you want.
There are different RSS Readers available for different platforms: Amphetadesk (Windows, Linux, Mac) / FeedReader (Windows) / NewsGator (Windows - integrates with Outlook).
There are as well different web-based feed readers available: My Yahoo / Bloglines / Google Reader.
Once you have your Feed Reader, it is a matter of finding sites that syndicate content and adding their RSS feed to the list of feeds your Feed Reader checks. Many sites display a small icon with the acronyms RSS, XML, or RDF to let you know a feed is available.