Everybody else, minus those who have never heard of it. Or something like that.

Seriously, though, the best I could find were the creators of http://americancensorship.org/ I'm sure that there's a lot more opposition than just the people who created that, but that site doesn't appear to have a supporters page that one can sign on to. Or if they do, I missed it.

Not official, but http://www.cdt.org/report/list-organizations-and-individuals... has a long list of letters of opposition and concern from a wide range of organizations and individuals addressed to congress.

I am surprised Visa is both in proponents and opponents list. :)

Hedging their bets I guess.

Common to donate to both the Republicans and the Democrats, because no matter who wins they're ingratiated to you.

Why supporting and opposing a piece of legislation makes sense I don't know