The first is Defense and the National Interest, run by Chet Richards, one of John Boyd's acolytes, and the number one repository of John Boyd and 4th Generation Warfare material you will ever find. The second is Abu Muqawama, run by former Army Ranger Andrew Exum, a fellow at the Center for a New American Security, who announced that he would be curtailing his daily blogging activities.
What's distressing is that both have made the decision to shut down based, in part, on what I describe as jackassery in their fan base. DNI reported numerous security threats, and Andrew Exum drew the line with a post in a blog which called for his crucifixion.
It's truly a sad day. I wish both of them the best.