QUOTE(hboss @ Sep 15 2011, 01:22 PM)

internal CSS :
An internal style sheet is a section on an HTML page that contains style definitions. Internal style sheets are defined by using the <style> tag within the <head> area of the document.
External CSS :
An external style sheet is a file with a .css extension that contains style definitions.
Very good definition of CSS but what about RSS?
RSS:RSS stands for Really Simple Syndication. Its a web feed which provide us the updates if you subscribe.