Thanks esmi.
I just checked every available RSS reader. Safari is getting the full feed, but every other browser and reader app and even Google Reader is should the summary feed.
That tells me it's not something on my computer's end. Your pastebin post, along with the Safari success, tells me the full feed is at least getting out.
So that seems to narrow the problem to something about the RSS feed not producing a widely readable result.
I checked the feedburner feed, and sure enough, just where you would expect the full post, there's only gunk. See line 23 here: http://pastebin.com/1MyT7q1k