We changed the URL from http://neverworkintheory.org/2016/10/05/test-driven-developm..., which points to this.

When the topic is controversial and the paper is not so specialized that only a few people here can understand it, changing the URL to that of the paper tends to help make a discussion more substantial. Especially when the blog post is more of a gloss on the paper than an in-depth commentary on it.