@elby: Just talking about it when and where you can still helps. I stopped giving Blizzard money after the Blitzchung incident, so I can't give them any less. I can, however, let anyone I know who does give them money know what's going on if they don't know already.
Earlier today, I sent an email about this to the one friend I have who still subscribes to WoW. He just emailed me back saying he and his wife have now canceled their subs. For reference, he's center-right politically and was gushing to me about new WoW lore as recently as a week ago. I never would've expected him to actually boycott a company in this situation, but he has, and I'm glad.