1. A system comprising: one or more devices to: determine, at a first time, a first set of topics relating to content within a document; determine, at a second time, a second set of topics relating to the content within the document, the second time being different than the first time; identify a change in a quantity of topics between the first set of topics and the second set of topics; generate a score for the document based on the change in the quantity of topics; and rank the document with regard to at least one other document based on the score.
1. A system comprising: one or more devices to: determine, at a first time, a first set of topics relating to content within a document; determine, at a second time, a second set of topics relating to the content within the document, the second time being different than the first time; identify a change in a quantity of topics between the first set of topics and the second set of topics; generate a score for the document based on the change in the quantity of topics; and rank the document with regard to at least one other document based on the score. 5. The system of claim 1 , where the one or more devices are further to: detect a topic that is in the first set of topics and is not in the second set of topics; and classify the document as spam upon detecting that the topic that is in the first set of topics and is not in the second set of topics, the score being further based on classifying the document as spam.