Some of the most frequented websites are participating in a strike today against the Stop Online Piracy Act in the House of Representatives and the Preventing Real Online Threats to Economic Creativity and Theft of Intellectual Property Act of 2011, which is currently in the Senate. Sites planned to go dark, displaying links to different informational pages denouncing the two bills.

The two controversial pieces of legislature, which would expand the power of the U.S. Department of Justice to strictly enforce copyright laws on the Internet, have gained a large number of opponents, including President Barack Obama, in the past several months.

The initial idea for the strike came from reddit.com, a popular social media and news site.

“The freedom, innovation and economic opportunity that the Internet enables is in jeopardy,” the reddit team said in a blog posted on Jan. 10. “There are powerful forces trying to censor the Internet, and a few months ago many people thought this legislation would surely pass.”

The team then went on to outline its intentions to black out the site today from 8 a.m. until 8 p.m., greeting visitors with a display of only anti-SOPA information and re-streaming the hearing of the bill that took place in the House last month .

Internet giant Wikipedia, which also opposes SOPA and PIPA, expressed intentions to join Reddit in the blackout shortly after. Unlike Reddit, however, Wikipedia’s blackout, which is limited to its English language site, lasts for 24 hours. It began this morning, at midnight Eastern Standard Time.

“We believe that new proposed laws like SOPA and PIPA, and other similar laws under discussion inside and outside the United States — don’t advance the interests of the general public,” Wikimedia Foundation Executive Director Sue Gardner said in an open letter to English Wikipedia readers and community.

Google is also participating in the day’s protests, though not with a total blackout. Google users will be greeted with an anti-SOPA / PIPA link. Twitter users are also being encouraged by sopastrike.com to “tweet like crazy” using the hashtag #SOPASTRIKE.

Other participants today include Firefox creators Mozilla, popular blogging site WordPress and the owners of the Cheezburger Network, who operate sites such as FAIL Blog and Memebase.

While SOPA has been put on hold in the House, a vote on PIPA will take place in the Senate on Tuesday.