As announced, Wikipedia's main page is "blackened" today in protest of the controversial Stop online privacy act (SOPA).
"For over a decade, we have spent millions of hours building the largest encyclopedia in human history. Right now, the U.S. Congress is considering legislation that could fatally damage the free and open Internet. For 24 hours, to raise awareness, we are blacking out Wikipedia," says the message on the page.
The actual articles on Wikipedia are actually accessible for a short period of time, after which they redirect the visitor to the blackened main page.
For millions of Wikipedia visitors today, the message will be clear: one of the most influential sites and communities on the internet is clearly against SOPA. Many other sites, including Reddit, will join the protest by shutting down or "blacking out" their homepages today.