Google has added subscriber stats to their Webmaster Tools. This is a nice addition, however I noticed it was only working with internal feeds and not Feedburner. I left a comment and hopefully this problem can be resolved. The system works with any Google product for aggregating feeds.
The updates to the interface are nice and follow most other Google products with a smooth navigational feel.
We’re unrolling some exciting new features in Webmaster Tools.
Source : Subscriber stats and more