I have no idea whether this was an April Fool's-type joke, and I was largely ignorant of the significance of the defensedistributed.com domain anyway, though I was vaguely aware of but not overly interested in the technology used in the printing manufacture of gun components.
I had to do some googling on the subject to reduce my ignorance.
Discovery: Whoops! This looks like a pretty important domain to those who would see themselves as upholding and protecting the full intent of the Second Amendment, even as the latter seems to be undergoing a State-sponsored whittling-away under their very noses.
However, I am skeptical about this supposed domain seizure. It could well be an AF joke by (say) defensedistributed.com supporters, intended to make it look as though defensedistributed.com was a victim and was having the book thrown at it by the Establishment in order to kill it stone dead.
In which case, some people (not me, you understand) might say that this could presumably be an attempt at suggesting that, if defensedistributed.com has not in actuality done anything illegal yet - as a corporate person - and if it could also be perceived as a potential or real threat to the Establishment, then all due process within the State's ambit could (and just might) be brought to bear to ensure that defensedistributed.com and those associated with it were turned into or re-engineered in the public's eye as criminals and pariahs in society. However, I couldn't possibly comment.
We shall no doubt be told whether it was a joke.
Either way, one wonders what Julian Assange would make of this, or, for that matter, what Aaron Swartz (apparently regarded by many as a martyr to the cause of Freedom) might have made of it.