I don't think people really understand the ramifications of the law, and an example that affected them would do wonders for everyday internet users, with a side effect of drumming up needed media attention.
"A true blackout would be hellish: I don't know that there's a day that goes by that I don't read something on Wikipedia (which is the point, of course)."
I think a blackout would highlight just how many people rely on Wikipedia and might bring to light that they wouldn't mind donating a few dollars a year to keep it around.
Sadly, it failed as ISPs are now censoring 'voluntarily' by forcing it onto their customers [0][1], and the government is funding them. Amazingly, many Australians don't know that Australia's internet is censored now.
[0] http://www.news.com.au/technology/internet-filter/telstra-op...
[1] http://delimiter.com.au/2011/12/11/isps-wont-talk-about-inte...
A simple, but effective, solution would be to simply change the site's style to draw all article text with a black background, a la redacted documents.
If this was done, users could still manually highlight using their browsers to view the text (and screen readers would still work just fine), but the effect would be still be striking, to say the least.