You may have received an email yesterday or the day before from Facebook that caused you to delete it, thinking it was spam. In fact, it's just the opposite. Though this feature hasn't been formally announced by Facebook themselves, it's part of a bigger plan called "Post Insights" that was introduced in February. Facebook appears to be adding another level of metrics for Fan Page administrators: weekly email reports.
Go back into your trash folder and retrieve that email to find information like, how many Facebook fans your page received this week, how many wall posts and comments were featured and how many visits your page had. Not sure what this email looks like? Below is what we received for our Upright Communications page.
Social media measurement includes keeping track of your "fan base" and how often they interact with you. It's nice to see that Facebook is now providing these metrics and will continue to upgrade their reporting features in the future...stay tuned!