Interesting. We'll have to see what sort of backlash this generates, pro and con. Woulda been funny if you hadn't warned me Borek:, I check Wikipedia pretty much every day, usually late at night, when something comes on TV and I want to know, "What else has he been in?", "What other things has this director done?"
Still, while I recognize that the SOPA legislation is on some level, stiffing the ability to share information, under some sort of blanket cover of "protecting intellectual property", I wonder how it really affects the sort of thing on Wikipedia itself, not Wilkimedia Commons, or other parts, but the encyclopedia parts of Wikipedia -- the parts I use to find facts about a chemical that's mentioned here for example. That seems not to be the sort of thing SOPA would be needed to protect. Likewise some actor's next movie or the listing of his ex-wives. Maybe by throwing a fit and blocking all that information in reaction to SOPA would seem like a childish fit and just be ignored.
Don't forget, the ultra-right ring groups in the US government are at times openly derisive of the internet. They've formed a meme in their minds that its just unfairly hostile to the right wing and right wing interests. They might not be frightened by the possibility of the brief loss of even a significant internet resource such as Wikipedia.