What Are RSS Feeds?

Really Simple Syndication (RSS) is an XML-based format used for content distribution and syndication. Subscribing to RSS feeds allows you to receive custom, up-to-date information from your favorite online content sources without having to regularly check the site for updates.

How to Access RSS Feeds

News readers that display RSS feeds from the websites you specify—they check the RSS feeds you have subscribed to and display new items from each feed. You can download news reader applications for your computer, and here are also many popular web-based news readers available, such as Google Reader and Bloglines. Some web browsers and email applications also have RSS capabilities built in.

You can see a list of many available news readers at Wikipedia.

YouTube offers several RSS feeds for categorized groups of videos (such as recently uploaded, top viewed etc) as well as customized feeds for users and tags.

	To subscribe to categorized groups of videos, simply go to the category you want (for example, “Most Viewed – Today“). Then click on the orange ‘RSS’ button. This should trigger your chosen news reader to add the subscription.
	If your browser has RSS capabilities, then you can add the feed there. The command varies between browsers, but can usually be found on the ‘File’ or ‘Bookmarks’ menus, and will be called something like “Subscribe to this page” or “New Live Bookmark”.

source: http://youtube.com/t/rss_feeds