The first issue of Growth Hacking Digest featured a link to a post by Casey Winters, PM of Growth at Pinterest. I recently had a conversation with Casey in which he graciously pointed me to an updated presentation of those same SEO concepts. Watch and learn how to do SEO at scale, it's not just adding more content.
This Youtube video is a moderated panel with CMO's from Facebook, Slack, and Zynga on early-stage marketing for startups. They discuss how to optimize marketing ROI by aligning growth and brand teams, listening to user feedback, reviewing engagement metrics, and hiring the right marketing talent at the outset.