Megaupload.com is down.
It has begun.
If SOPA passes, consider Facebook, Youtube, Twitter, and every other major website like Megaupload to be shut down as well, that's why millions of people have signed letters in protest, it's why Wikipedia/reddit/google did did their blackout/protests, etc, because if that bill passes, everything can be shut down, including MMAF if anyone were to post any form of copyrighted material.
I highly suggest anyone who cares about freedom to write your congressman, write Obama himself to veto it if the bill goes that far (over 80,000 people have done so), and take part in any events that you can to stop this nonsense.
for more information.