FeedBurner is having a reporting failure yet again. I have received at least four emails and several IMs since April 1st from concerned bloggers that their FeedBurner subscribers numbers have dropped. I personally saw this myself, where FeedBurner is reporting only 8,000 or so subscribers to this site, when in fact, we normally have 20,000+.
The issue? Googler Matt S. confirmed the issue in a Google Groups thread, saying that FeedBurner is having problems retrieving the accurate numbers from Google Feedfetcher. Google notified the Google Feedfetcher team and they hope it is corrected soon. Here is a screen shot showing the huge discrepancy between March 31st and April 2nd, in terms of the numbers reported from Google Feedfetcher, typically people's most popular RSS syndication service. The difference is 9,842 subscribers versus 18 subscribers.
Here is Matt's post:
If you compare individual days (e.g., March 31 vs. April 1) in Analyze > Feed Stats > Subscribers, I'm guessing most of the missing subscribers are from Google Feedfetcher. We've notified that team of the temporary drop in subscribers we're seeing reported by them and will work with them to resolve the issue.
These issues happen fairly often, so when you see it, don't worry. It is very rare that you would lose 50% of your subscribers overnight, even if you did touch the Queen of England.
Forum discussion at Google Groups.