While I'm not a conspiracy nut, I can say yes I believe FBI likely keeps tabs on places like GFY.
This was re-posted on a very old school hackers forum. This is a copy of the guy's post that was deleted multiple times on Slashdot.com talking about how the FBI monitors forums and the tactics they use.
http://cryptome.org/2012/07/censored-slashdot-post.htm
This is the actual information he was trying to post.
http://cryptome.org/2012/07/gent-forum-spies.htm
You don't have to be a conspiracy nut to understand why the FBI would monitor places like this and other popular forums on the net say various hacking sites or even places like AR15.com