RSS (RDF Site Summary) is a standard format for delivering articles such as news headlines and summaries.
To subscribe RSS feeds, you need a program that can read the RSS format. Several modern browsers and email programs have built-in functionality for this. There are also several free programs. The programs will notify you when a new article published and you can seamlessly monitor an RSS feed, without having to visit the sender's website. Article title is a link to the full article.
Examples of some free software that can read the RSS format:
Feed Reader for Microsoft Windows.
NetNewsWire for Mac OS X.
Bloglines, free Web service.
Mozilla Firefox, Web browser with built-in RSS reader. Windows.
Internet Explorer 7, Web browser with built-in RSS reader.