Apparently Feedburner, the service through which I send said emails, had a little glitch. So if you see this, know that I'm still running amok, but there might be a little delay getting it to you
14-MAY 2008: Our email delivery system did not poll some FeedBurner feeds for updates on 13-May; as a result emails were not delivered and email subscribers were not reported to FB subscriber totals for that date. We're investigating this issue.
UPDATE 12:00 CST: We restarted the polling process; starting now, any feed changes not yet delivered via email should be detected and delivered, albeit up to three days late, and from this point forward on your regularly scheduled window. We regret this error!
You may still see 0 email subscribers reported on your Analyze tab's Feed Stats view for Wednesday 5/14; this should be the last day with no reported email subscribers in this stretch. (Don't forget your subscribers didn't just up and disappear; they're still listed under Publicize > Email Subscriptions > Subscription Management.)