Wikipedia and Google are concerned that the legislation, if passed, could be used to target legitimate sites where users share content.
The 24-hour Wikipedia blackout is an unprecedented move for the online encyclopedia. However, it's not complete: the block can be bypassed by changing browser settings, or by using the version of the site designed for cellphone screens.
Clicking the blacked-out logo on Google.com takes surfers to a page where they can add their names to a petition against the bills.
