whitehouse.gov is not a scam site nor are most of the petitions on the site are not a "scam". Granted there have been some really dumb petitions posted on the site (such as one demanding that Justin Bieber be deported back to Canada :d oh
, as anyone can make a petition on the site. But those petitions are usually reported and taken down. The petition to stop SOPA would not be taken down from the site as it is an issue that the common people would be concerned over and would be impacted by. The point of this website is to be the voice of the people and their issues.
How this websites works is if there is an issue going on that the people are very concerned about they can create a petition, if 100,000 people sign it then it is immediately delivered to the white house for review. Of course this does not mean that the issue will be remedied, but it will get a chance that otherwise where it otherwise would not.
"The right to petition your government is guaranteed by the First Amendment of the United States Constitution. We the People provides a new way to petition the Obama Administration to take action on a range of important issues facing our country. We created We the People because we want to hear from you. If a petition gets enough support, White House staff will review it, ensure it’s sent to the appropriate policy experts, and issue an official response."The author probably didn't post the link correctly.
I did a very quick search and found this petition just recently created on the site;
https://petitions.whitehouse.gov/petition/stop-sopa-policies-trans-pacific-partnership-notice-and-staydown-efforts-and-other-policies/dXMRvNh8As for SOPA I really highly doubt anyone has to worry about them or newer versions of them, it would be pretty much impossible to regulate the amount of fanworks that is in existence. They can try all they want, but it probably will never be implemented.
Edit: Sorry if the first version of this seemed a little abrasive, I did not intend it to come off as such, just practical and informal.