That's a good point about polls vs. votes (and still more reason to support IRV, where people would be more likely to vote their true opinion). As for the Zogby poll, that's "likely voters", but I'm guessing Nader was referring to the Gallup poll of registered voters that put him at 6% as of June 21-23 (although he's dropped to 4% in the latest poll, which hadn't been released at the time of the debate—I'm guessing that's part of the "Edwards bounce").