I’m speaking for myself, not on behalf of National Geographic when I say that if you do not know anything about SOPA, all you really need to know is that you should be against it. Go here for a very brief overview and to show support: https://www.google.com/landing/takeaction/

and here to learn more about the specific details behind SOPA:
http://mashable.com/2012/01/17/sopa-dangerous-opinion/#43847Jan-18-A-Day-of-Protest

Tumblr and many, many, many other sites would be censored and not function if SOPA were to be passed. (This site would definitely violate SOPA terms.)

So participate against this :) and try to have a nice day,
~your internet-loving moderator