A developer writes: "Half of the stuff I'm hearing says I should send RSS 2.0 as text/xml, the other half says application/rss xml. What's the best practice?"
Content-Type には text/xml を使おう、な Dave Winer の意見。
application/xml というチョイスはないのかしらん。
http://www.hyuki.com/diary/dia0404.html#i16_13