I want to tell you this puzzle about my feeds. I use FeedBurner for my RSS feed. When i was using this green theme (my last one) i got about 30 readers. Now several days ago i change my theme to this 3 column K2. It has subscribe element in the good placement (at the top right spot) but i am not sure if this was the reason why i got next day over 200 readers, new readers…. well i am not sure ?
Another change that could make this was updated FeedBurner 2.1 plugin.
And the new version redirect better all users from regular RSS to FeedBurner service:
The plugin will detect all ways to access your feed (e.g. http://www.yoursite.com/feed/ or http://www.yoursite.com/wp-rss2.php, etc.), and redirect them to your FeedBurner feed so you can track every possible subscriber.
Anyway see my stats to believe it was only one day:
So till today i don’t know the answer 
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Alican
Peter
TheWeblogZone
That’s because all the other folks that were downloading the feed were redirected to the Feedburner link. That’s what the plugin does, move the feed-reading people to the Feedburner link. The stats will shoot up dramatically, because those once using the normal WordPress feeds will now be using the feed provided by Feedburner.
It simply shows that now all your subscribers are on Feedburner, and you are counting them correctly.
Yee probably that was the reason for all that