Now question is that What does it tell us?
Subscribers is a measure of how many people are subscribed to your feed. At any given time, you can expect that a certain percentage of this subscriber base is actively engaging with your content and this “Reach” measurement provides this additional insight.
One more thing, there may be people viewing your content beyond your known subscriber base. For example, they may view your content on a feed search engine or news filter site.
Reach aggregates both of these groups, providing an accurate and useful measurement of your true audience.
How is reach reported within FeedBurner?
reach look like this:
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