About RSS

An RSS "feed" simply feeds (or gives or transfers) an XML file (or XML data in text format) to a program that knows how to interpret the XML data (like Wimpy or iTunes or some other "aggregator" type application).

Said another way:
The terms "RSS" and "XML feed" and "RSS feed" are interchangeable descriptions of the same thing -- just a bunch of text-based XML data that is organized in a particular way.

And another:
RSS stands for "Rich Site Summary" it's a way to summarize headlines and brief descriptions of headlines (like the front page of a news paper) so that both humans and computer programs can read it with relative ease. Podcasters have adopted this format since it already includes a standardized way to include an mp3 (audio/video/image/other) file in the description. (Why re-invent the wheel? -- Especially when the RSS format is [and has been] used by the major newspapers to transmit news and information for years.)

And another:
RSS is a "standard" for formatting XML data in a unified way so that programmer geeks can all be "on the same page" when they have to write a program to "read the feed" and present the data contained in the XML inside of a program (like Wimpy or iTunes or an aggregator).