Built into Facebook is Facebook Insights, which provides data on user interaction with your Page, demographics, and performance over time. Only Page administrators, application owners, and domain administrators can view Insights data for the properties they own or administer. Insights is a free service for all Facebook Pages and Facebook Platform applications and websites.
The key with any of these social media monitoring tools is using them to read between the lines. Some of these tools do it for you--connecting dots between hard numbers to draw conclusions--and some require you to do some or all of the dot connecting yourself. In fact, that's the basic difference between monitoring and listening. Monitoring is a matter of gleaning hard data; listening is taking that data and looking at it--over time--through the lenses that are relevant for your company. According to JoAnna Dettmann, co-founder of digital marketing firm tSunela, "By listening to what target audiences are saying, you have this unparalleled opportunity to respond to their comments and criticisms and make strategic changes based on this feedback. It is a 24/7 focus group, test market discussion and comment box rolled into one."
This list of social media monitoring tools is by no means comprehensive, but does provide some suggestions for (mostly)low-barrier-to-entry monitoring applications.