I noticed today that my feed didn't validate. So I updated the format to RSS 2.0 and added a new plugin to correctly set the <category> element from the directory path before the post name. Then I took the named anchors out of the HTML story template (I don't think I ever used those) - so the RSS and HTML pages each validate now. Woo for syntactic correctness!
Then I fixed the warning about HTML in title tags (ugh, v2.0 of RSS is really underspecified) and about the relative URL I used for an image link, which fixed the feed validator's interoperability complaints.