Thanks for all of these ideas!

A quick update: Our SEO expert seems to think it's because of duplicate content. Ironically and interestingly, it's our syndication partners that are republishing our content -- big outlets like AOLJobs, Business Insider, Chicago Tribune, etc. -- but it looks like Google thinks we're the republisher rather than the content creator because those outlets are bigger. We're now taking steps to move away from allowing big outlets to republish our content!