Cameron Neylon has "The Embargoes Don't Work: The British Academy Provides the Best Evidence Yet" in PLOS Opens.
Here's an excerpt:
Embargoes are an artificial monopoly created to make the competition a bit less fierce. But truly, if a publisher believes that they add value and wants to be competitive then why should they fear a Word doc sitting on the web? Indeed if they do it suggests a lack of confidence in the additional value that they offer in the version of record. The best way to give yourself that confidence is to be tough on yourself and take a good look at how and where you add value. And the best way to do that is to compete successfully with "free."