Imagine you wanted to fetch the entries on a facebook page and its related comments to bring it into another application. That works fine using the facebook API.
But if you want to track and fetch only those 'new' comments to previously already fetched posts, is it possible?
Yes, you can use FQL and query the tables directly
https://developers.facebook.com/docs/reference/fql/
https://developers.facebook.com/docs/reference/fql/comment/
You will of course need to keep track of the last time you checked for comments for a given post, and constrain the query with the
time
column.