Google released an experimental "Google FeedBurner" interface that now provides "real time stats for clicks, views, and podcast downloads," which means you can start seeing what content is drawing traffic from feed readers, Twitter, and other syndicated sources as it happens.
Additionally, if you use FeedBurner Socialize service, and PubSubHubbub or you ping Feedburner when you post, you can get stats on how much traffic your feed items are receiving from Twitter, as well as feed reading platforms like Google Reader in one place.
Your subscriber and reach numbers are still calculated based on a whole day's worth of requests, and are based on traffic you received yesterday and before; but your item stats reflect the traffic you're receiving right now.
The best way to see these real time features is to publish a new post and then switch to "Last two hours" view to begin seeing updates.
To use new interface visit here or logging into feedburner.google.com and then clicking "Try out the NEW (beta) version!" link at the top.