Friends Timeline Feed Doesn't Contain Friends?

I feel like I must be misunderstanding something here, but my friends' timeline feed (http://readernaut.com/feeds/rss/matth...) contains only my activity, even though my friends' notes feed (http://readernaut.com/feeds/rss/matth...) shows that my friends have posted notes.

As I've said on Twitter, I'm not even sure why my friends' timeline feed contains my activity at all, but I'm more confused about why it doesn't contain my friends'.

OT, the RSS feeds are being delivered as text/xml. Not a big deal, but some applications (web browsers) will do a better job of displaying feeds when the correct mime type is used.