I don't dislike fighting dirty when it really counts, but realistically this strategy would never work. First, such actions would not stand long-term, because the government can merely prohibit withholding services from government agents, and sanction any companies who do. You delist certain senators from google? That is (insert violation of law or ethics here, real or conjured), you are fined $1 million a day until you de-de-list us. And they could make the fine as big as they wanted, and google (or whomever) would buckle. Make no mistake: the government has the power over long-term behavior, not corporations. And second, the government knows such a boycott would not be able to stand up against their power, that it is an idle threat, and so they would call their bluff and vote for SOPA anyway.
You can't win a fight by threatening to beat the bully up tomorrow and the next day and the next day for taking your lunch money today. You have to win the fight now, before the damage is done.
Add in the additional problem that it is much easier to pass (or block) legislation before it passes than it is to repeal, and I don't think this strategy is viable. If it were, google and other companies could get together now and force the repeal of legislation already in place that is distasteful. How likely is that? On the other hand, the original nuclear strategy mentioned in the article would indubitably have an immediate and unbelievably tremendous impact. We're talking shock and awe here, folks. If google didn't work for a day, every voting person in America would know about it.
And that's the way they pass legislation that the majority of people wouldn't like if they knew the truth about it -- by sneaking it through because, frankly, most people are just too busy or too apathetic to not fall asleep when someone mentions the word "politics". The actual nuclear strategy mentioned in the article would certainly wake them up, and in a big way.
That said, unfortunately I doubt google or any other publicly traded company has the balls to do it.