12. The computer-implemented method of claim 11 , wherein building the corpus comprises: parsing the first collection of documents to identify secondary sources, wherein each document in the second collection of documents is available from a respective one of the secondary sources; and accessing each secondary source to identify documents to add to the second collection of documents.
12. The computer-implemented method of claim 11 , wherein building the corpus comprises: parsing the first collection of documents to identify secondary sources, wherein each document in the second collection of documents is available from a respective one of the secondary sources; and accessing each secondary source to identify documents to add to the second collection of documents. 13. The computer-implemented method of claim 12 , wherein evaluating the corpus comprises: identifying topics, concepts, or subjects referenced by documents in the first collection of documents; and determining indications of opinions expressed about the topics, concepts, or subjects referenced by documents in the first collection.