Courtesy of the D.C. 501 tech club discussion list -- these are nonprofit listservs for informal conversation about nonprofit technology -- comes Phil Shapiro's very nice explanation of RSS feeds. The concept is still a little opaque to many (pending an incoming generation of software in which the tool figures to be more seamlessly integrated into browsers and mail clients), although standardized data feeds are what makes most of the cool new web stuff go.
This is a good place to start if you've been reluctant to shake hands with another web 2.0 acronym even though you know you should; between Phil's article and its bibliography, there are plenty of links to good feed-related tools and resources worth a skim-through for any level of expertise.