Proper/Possible methods for extracting unstructured data from websites
You need to build a couple of classifiers. First, you need a classifier to give you thumbs up that you want to parse the page at all. Call this the "is_relevant" model. Once you've determined that a page is relevant, you should pass it through a separate classifier for each data element you're hoping to capture (or a multiclass classifier capable of recognizing each of those elements and distinguishing them from content you're not interested in).