Understanding topic classification

In Chapter 2, Detecting Spam Emails, we learned how to classify incoming emails as either spam or ham. Undoubtedly, quarantining unwanted correspondence in the spam folder is an excellent feature for any email application. But is that enough? Still, ending up with a large number of emails stacked in your inbox can be an equally unpleasant situation. For this reason, creating personalized folders to accommodate each item and facilitate either responding to or archiving email threads is common. This necessity is even more acute for companies or large organizations that offer a generic contact account for external people. Hence, the appropriate personnel or department must process a large volume of incoming questions, announcements, offers, and complaints. This task can be cumbersome for a single person, while an automated system can check every email and decide who its recipient should be.

Besides emails, businesses deal with many other unstructured...