Facebook has added a new feature to the Insights function of your Facebook page. If you look in the left column, underneath the count to show the number of people who like your page, you will also see a count for the number of people “talking about this”.
This basically means the number of people who have engaged with your page (commented on a post in your Wall, for example) within the past 7 days.
The Insights feature is useful as well, because it shows you information about the gender and age of your page fans, as well as the visibility statistics for your wall posts. Insights will also tell you which posts had the most interactions.