At deviant art, we're a community of artists. Often we will paint and create our own tributes to art work or characters created by other famous artists we adore and idol. Not only is this paying homage to them but it also helps to boost our own profile and exposure as the subjects are well known and highly searched for. They assist us in gaining fan bases when we move on to more original works.
Provided we don't sell this work, unless at a convention - it's perfectly legal and the owners of the intellectual property of the subjects usually don't mind fan art and some, like Marvel even encourage it since it's where they source their new artists from. However under the SOPA act this will consider all our fan work illegal and pirated, censoring our galleries. Only 100% original works will be permitted to sit on display in our galleries. Even worse, if someone comes along and attempts to provide proof, even if it's dodgy that they were the ones who created our artwork, there won't be any investigation and our work will be censored immediately. As you can image, the entire community is up in arms about it and many members are joining the black out/ censor protests.
However the site DA itself feels it's better to inform it's members about the bill rather than black out their site to protest a blackout (irony) - many individuals have taken steps to provide a snapshot of what the censoring would look like. Here's one example: http://swamperts.deviantart.com/
I decided instead of deactivating my account like many others, this seemed to be a more point making option and followed suit with my own custom content blocked sign: http://spudfuzz.deviantart.com/