众所周知Feedburner或者其它Feed烧录服务都无法统计Google Reader对某个Feed的订阅数量，不过现在已经可以了哦！！

Does Google Reader report subscriber counts?

Yes, Google Reader reports subscriber counts when we crawl feeds (within the “User-Agent:” header in HTTP). Currently, these counts include users of both Google Reader and the Google Personalized Homepage, and over time will include subscriptions from other Google properties.

详情参考Google Reader: Tips for Publishers及One subscriber, two subscribers, three…