Over the last week, and as reported in the FeedBurner status blog , we experienced a technical issue that caused us to report reduced subscribers from Google Feedfetcher in your feed analytics at FeedBurner and AdSense.
Our engineers have resolved the issue, and been able to rebuild stats from our logs such that the totals should now be correct. Please note that in the past, we were not able to correct historical statistical anomalies, but are now able to do so, always using the actual traffic data.
No data was lost during this process, nor were any subscribers actually unsubscribed from your feed. All feed content was delivered to all subscribers who wished to view the content, regardless of the numbers reported. Ad impression reporting and revenue were unaffected by these subscriber reporting issues.
We apologize for the inconvenience and appreciate your patience as we continue to merge our systems with other Google systems behind the scenes.