The European Union, the US and 7 other countries signed it so far. There's also the TPP(Trans-Pacific Partnership) which is I quote:
The Trans-Pacific Partnership Agreement is a trade agreement currently being negotiated by the United States and eight other countries. Like ACTA, the TPP is being negotiated in secret, and on a fast timetable. We don’t know what’s in the TPP IP chapter, and that’s what worries us. Entertainment industry executives who are members of the Industry Trade Advisory Committee will likely get to see the agreement drafts – again – but the rest of us will be kept in the dark unless we speak up now.