anyone know what it is in reference to? if you visit their page they tell you to contact your representatives
Check out Google, they're participating too. It's a protest against SOPA and PIPA. Basically, legislation that will give the government the power to indefinitely black out websites, without trial, that they deem are infringing or pirating intellectual property. It began with bipartisan support but it was met with some fierce backlash. It's being back by Hollywood and other media sources but being opposed by many large online sites (Google, Wikipedia, Reddit).
by the way: SOPA is not dead yet http://torrentfreak.com/sopa-is-baaack-120117/?utm_source=dlvr.it&utm_medium=twitter