I have revamped and updated my site: http://www.whats-new-in-biztalk-2013.com/ This site is dedicated to my course at Pluralsight with the same name. While this course was geared to BizTalk 2013, a lot of the content is still relevant for BizTalk 2013 R2.
This course has 6 modules:
BizTalk Server 2013 Overview
Using Windows Azure Service Bus with BizTalk 2013
REST Adapter Deep Dive
SharePoint Adapter Enhancements
Using BizTalk 360 with BizTalk 2013
Setting up BizTalk 2013 in Windows Azure IaaS
Of these, the module on the BizTalk REST Adapter is one of the best in the course! It is a great resources for anyone working with the REST Adapter in any version of BizTalk.
In the SharePoint chapter, I walk through integration with SharePoint Online in Office 365.
Check out the http://www.whats-new-in-biztalk-2013.com/ to see a 7-minute sample video.
As always, anyone can get a free 7 day, 200 minute trial of Pluralsight.