Videos
React.js Conf 2015 - Data fetching for React applications at Facebook by Jing Chen / Daniel Schafer. Introduction video to GraphQL and Relay.
Mutations and Subscriptions in Relay by Laney Kuenzel. A dive into how the Relay framework makes it simple for developers to implement mutations (data writes) and real-time updates.
Note: I'm still waiting for JSConf US 2015 to actually release the video. The speaker notes are quite detailed but I think it would be a lot easier to understand with the actual talk :)
Joseph Savona - Relay: An Application Framework For React at react-europe 2015 Follow-up talk on Relay.
Articles
https://facebook.github.io/react/blog/2015/03/19/building-the-facebook-news-feed-with-relay.html