RSS data files are simply the latest news of the site as the title, publication date, and description. The program that reads the RSS will be responsible for giving style or appearance to data included in the file and present them to the user in an attractive and readable way.
Thanks to aggregators or readers of web sources (programs or sites that allow reading web sources) can be obtained summaries of all the sites you want from the desktop, email programs operating system or through web applications that run as aggregators. No need to open the browser and visit dozens of pages.
Some popular aggregators: