I've studied the Stack Exchange API to some extent (although I'm a newbie to such things), and it appears I can query the database using many criteria. But does Stack Exchange store any "trends"? For example, among the set of tags [A, B, C, and D], which one had the most questions and/or the greatest increase since last week? I'm guessing I have to keep my own local database and draw my own conclusions by running a set of queries on a regular basis. Am I right?