Cynthia at Google Groups must be a new FeedBurner user. After all, Feedburner has seen regular drops in subscriber count (maybe once or twice a month) and even ran into a zero subscriber count issue with some users earlier.
But Cynthia dropped 300 subscribers yesterday, according to her FeedBurner count (which makes her lucky, because I dropped 700+). What could have possibly been wrong?
From Google FeedBurner's team, Matt S. informed us that there were issues with FeedBurner and Google Feedfetcher. Naturally, when you get a drastic drop in subscribers, it's no reason to be alarmed; it happens way more often than it should.
Personally, I think asking my peers on Twitter is a great way to be kept abreast of the situation. :)
Forum discussion continues at Google Groups.

Comments:
Fritz
10/26/2008 08:35 am
It seems that Feeds.feedburner.com has been listed for webwasher. Webwasher is a service for Internet-Proxies and is used for corporate networks in europe. It filters ads, video and adult content before it gets in your intranet. A Week ago Feedburner.com was listet as "Entertainment".
David Bradley
11/06/2008 11:26 am
I've given up worrying about feedcount as long as the trend is upwards you shouldn't be concerned, it's usually reporting errors or simply the day of the week that's to blame for fluctuations rather than subscribers leaving en masse.