The acronym RSS stands for Really Simple Syndication, and is used to describe the technology used in creating feeds.
RSS feeds provide frequently updated content published by a website. They are commonly used for news and blog websites, but are also used for distributing other types of digital content, including pictures, audio, or video. Feeds can also be used to deliver audio content (usually in MP3 format) which you can listen to on your computer or portable device. This is referred to as podcasting.
A feed can have the same content as a webpage, but it's often formatted differently. When you subscribe, the web browser automatically checks the website and downloads new content so you can see what is new since you last visited the feed.
You will need an RSS reader. Some browsers have built in rss readers that can be utilized. (For IE8: Add each feed manually by clicking on next to the feed.)
No, it's usually free to subscribe to a feed.
Sources: Internet Explorer (IE) Help Section (F1); SiteMaker CMS, Google