What is RSS / Feeds?
RSS / Feeds is a technology used by millions of computer users nowadays to keep them self updated with the latest happenings from their favorite website without the need of manually visiting the websites regularly. Its like taking a subscription of the website where you find useful content and don't want to miss any information. And yes it doesn't even cost a penny.
However note that its not like free magazine subscription those are delivered to your doorstep. Instead, you will need a Rss / Feed reader for reading the feeds. You also have the option of subscribing via email so that new updates are delivered right to your mail inbox. For reading feeds, you can try Google Reader that works both online & offline (with Google Gear).