XML or RSS. What's the diff?

[WallaceCleaver]

What is the difference between a .xml file and a .rss? Why would I want to name my syndication file with one extension over the other?

[choster]

XML is a family of languages, of which RSS is one subset or variety. As for filename extensions, it's entirely up to you.

[TheDoctor]

Which is the favourite? I swing between .rss, because that's the kind of newsfeed I'm constructing, and .xml, because that's what defines the content.

Anyone got a killer reason for one or the other?

[MaxM]

I use rss.xml :)

(Atom feed is named atom.xml)