Big Picture
Great overview of the content strategy field. Start here.
Interesting approach to developing content tactics that are tied to personas.
Content Testing & Metrics
Good summary of how to approach ROI with clients.
Thoughtful analysis of using analytics to drive content planning.
Deliverables
Comprehensive list of content strategy deliverables from Intentional Design.
Governance
Inventories, Audits, and Analysis
Messaging, Voice and Tone
Modeling and Structure
Nice overview of the integration of CMS and content strategy. Follow the links -- lots of good ones.