Classifiers are used to say whether a page has or does not have a property. The Manage Classifiers activity let's you create and manage the classifiers for this Yioop system. Creating a classifier will take you to a page that let's you train the classifier against existing data such as a crawl indexed. Once you have a classifier you can use it to add meta words for that concept to pages in future crawls by selecting in on the Page Options activity. You can also use classifiers to score documents for ranking purposes in search results, again this can be done under the Page Options Activity.