Wikipedia is opposed to the US Stop Online Piracy Act aka SOPA and Protect Intellectual Property Act aka PIPA.
Other websites are also taking part in the blackout, such as Reddit and WordPress. For the full list of websites taking action against SOPA and PIPA today, check out the SOPA Strike website.
- wikipedia blackout and SOPA (orgtheory.wordpress.com)
- SOPA and PIPA – Learn more (wikipedia.org)
- SOPA/PIPA Blackout (guardian.co.uk)