This is great. I hope other major players (Google, Facebook, ...) participate in this blackout in some way. Not everyone reads tech blogs and major TV outlets would not cover it since they are in support of SOPA. A little video stream on the main Google or Facebook landing pages would go a long way to help raise awareness.
This is a good start, but if it's just Reddit going dark for a day, I don't think it'll amount to anything. It's not like Reddit hasn't heard of SOPA/Protect IP.
It's interesting that Reddit will get a huge number of hits by people going to see it go dark. Too bad there's no way to monetize a dark site.
Would wikipedia to join the blackout if me and half a million others donate $10?