As you probably know, I (like many other geeks) disapprove of SOPA, and am pleased to see an effort being made to raise publicity of it so hopefully we can get the thing entirely stopped. If we can do this for every future bit of IP-strengthening legislation that comes around, we'll be well-off, I think.
I do find it a bit odd that Wikipedia is getting involved, given Wikipedia's attempts at being an encyclopedia (nuanced/messy though they are) means that it has typically avoided taking sides on most matters, in order to provide both the actuality and appearance of reasonable impartiality. This is one (but not the only) reason not to permit advertisements on the site.
A more difficult matter is the question of consistency and proportionality. There are many bad things happening in the world; lese majeste laws in Thailand, extraordinary repression in North Korea, inadequate worker protections in China and many other parts of the world, squandering of human potential because of homelessness and poor investment in education, etc. Internet censorship is certainly bad, but it doesn't hold a candle to these other things. Some of these are distant (meaning we might not easily influence them, although we certainly might choose to impose tariffs, or is it that we just don't know about them?). Some of these are more complicated than we might think at first glance. Still, it does feel oddly selective that we choose this issue to focus on, and I think it's because many of us protesting have it so good that we have the luxury of protesting bad intellectual property/network governance policy. That feels a bit strange to me.
This unease aside, I hope SOPA either is defeated, or if the internets lose this one we use this to build enough of a movement to undo this and all the similar crap from the last 20 years.