I'm now using the aforementioned RSS Reader to read this weblog. So it has to be valid Atom, the content must validate when RSSified, and still validate when XHTMLified. Thus, to save hassle relating to escape characters and other such technicalities, I'm now using straight apostrophes as quotes. It's ugly, but it works.

Update: with the advent of the Mooquackwhatnotbot I'm now using proper HTML quotes - <q> and </q>. The usual disclaimer about Internet Explorer's crapness applies, as does one about Atom feed readers - they probably won't show any quotes.