https://www.graphicartistsguild.org/ !! :) They point to position statements ( https://twitter.com/#!/gaguild/status/150004542073872386 <- written by the copyright alliance) that speak to copyright and say the bill's scope is narrow and specific (I disagree), but I didn't see anything about technical concerns. I think it's fair to say those position statements are a load of horse shit.

"Sure we're giving the gov't the right to indefinitely detain anyone, but they're only going to do it if someone is rilly rilly bad, so don't worry! :)"* <- constitutional and civil liberties protections do not work this way.

*I know SOPA isn't the same, it's just an analogy :)