I keep seeing people commenting on these sorts of polls by stating that they don't matter because the number of people that posts in them is too small or because there are more people not on the internet then on it. Which shows a basic ignorance/misunderstanding of polls.
The size of the sample is less important then the way in which the sample mirrors the larger population. The percentage of gamers who post on ENWorld is irrelevant compared to the question of whether the gamers who post on ENWorld have the same overall buying habits as nonposters. I would guess the answer is no, but I would also guess that ENWorld Posters are representative of the more active buyers in the gaming community.
When I look at the two polls regarding the two companies, the first thing I notice is that both have a nice curve, which is a good thing in polls of this sort. The second thing I notice is that the #2 in the Paizo poll is slightly off the curve and makes me think if we increased the sample size, it would probably level off to being smaller than the 3.
Overall, if I was Piazo, I would be pleased with the Poll results, internet or no. And if I was WotC, I would be a little worried.