Some sites attempted to block them, but my understanding is that it can take 24-48 hours for an ad block to go into effect, which made that strategy essentially ineffective. Other sites pulled their Google ads for a few days, so that they wouldn't wind up showing the offensive ads on their site. I know that Joe Decker did this with his polyamory site.
I've seen a lot of outrage among my friends and acquaintances over this-- they were angry at the site (for example, Tribe.net) for accepting those ads, and angry at Google for taking money from Yes on 8. While I understand their anger, particularly at the brutal assault of bigotry that we got over the last few days, I believe that their anger is misguided.
The question comes down to this: should Google be in the business of choosing to run only some political ads, or should they give everyone an equal voice in their advertising? While I feel very strongly about equality and rights, I also feel very strongly that everyone should have a voice and equal access to media. I believe that Google did the right thing by running those ads.
Not accepting those ads would set a bad precedent. Do you really want Google to be in the business of choosing which political ads you should see? Would you like it if your local newspaper, radio station, or television station was only willing to run ads for one side? What if they only ran ads for the side you disagreed with? How and where should Google draw the line?
Free speech and giving everyone the chance to be heard is one of the highest principles of our country. It's very easy to defend speech that you agree with. It's much harder to say, "I think that what you are saying is vile, but I will fight for you right to say it."
To be clear, I have no beef with the sites who chose not to accept those (or any) ads from Google during that timeframe. However, AdSense is reasonably close to being a common carrier, and I would rather have them accept all campaign-related ads than to choose for me which messages I get to hear.
The real anger should be directed at the people who funded and placed those ads, I think. Or perhaps at the process that allows our constitution to be amended with a 50.1% vote.