1 No. They're just compiling their database and cross-referencing it against Facebook. When the end comes it will be swift, merciless and arrive wielding a very big net. 

2  Good thing I'm not on Facebook. (Or Twitter, or any othersocial media.)

3 I kinda wonder how they intend to track the torrenting for the 'Liberator' pistol plans.

4 The horse is out of the barn on that one. There's no way they get it back.

5 The Department of Justice has shown themselves perfectly willing to make an example of someone "pour l'encouragement des autres".

6

Mon ami, it is 'pour encourager les autres' if quoting Voltaire.

Trying to make an example of the Liberator blue prints or any other homebrew plans to discourage future downloaders will fail, given the intensity of feeling that has been whipped up.  If they can not even stop the downloading of the old US Army FM for improvised munitions, trying to to firearms designs will be like Don Quixote charging the windmill.

Of course, this is the federal government we are talking about.  Given their previous track record, they might just post some designs of their own on a department website because someone screwed up, similar to how the EPA once posted the confidential emergency/crisis action plans for every single industrial facility in the US (Detailing, among other things, all the known vulnerabilities of those plants.)...