+ if you go to http://www.marketingstudies.net and click to the red question mark (right of the red RSS-Button) this leads to an explanation from the view of using RSS for marketing purposes and to further leading links.
+ very good explanation also in the BBC Homepage
http://news.bbc.co.uk/sport1/hi/help/rss/3397215.stm
from the view of a news provider. Also information: How do I start using RSS feeds?.