I agree. The amount of response bias in this survey will tend to be absurd. I suspect most people who use facebook and/or twitter won't bother with answering this. There is no good reason to. I also suspect that people who don't use facebook or twitter will also be indignant about the fact that they don't use it and will make a point to vote against them. Heck even I have done similar stuff before. From the outset this survey isn't going to work if the methodology is not correct
34.5% of the people who took this survey claim they are not using Facebook/Twitter.