1.   Our outrage against SOPA had a long incubation phase.
  We knew about PIPA over a year ago.  Enough people educated themselves about it.  But instead of lapsing into apathy, they STAYED ANGRY.  People on reddit KNEW that SOPA would shut reddit down.  The anger kept people passionate about the issue.

2.  Powerful allies like Wikipedia.  When 96% of people have never heard of SOPA, then congress can 96% ignore the outrage.

3.  The media Presstitutes ignored or didn't cover SOPA, so they didn't have a counter-narrative to throw mud on SOPA opponents.