As a writer, I believe the current message ("The Wikipedia community has
authorized...") is long and wordy and therefore not likely to be read by most users.
I recommend shortening & simplifying it. Here's an example that removes 30+ words
and preserves the meaning:
WE NEED YOU TO PROTECT FREE SPEECH ONLINE
The English Wikipedia is "blacked out" for 24 hours to protest two bills before
the United States Congress, known as SOPA and PIPA. These bills endanger free speech in
the United States and abroad, setting a frightening precedent of Internet censorship for
the world.
Today we ask you to take action.
[[Take action]] [[Learn more]]
Just a suggestion.
DanB