Since it was an opt-in poll, perhaps it does bias things somewhat. All the same, the conclusion has to be that the active AB community (ie the ones that spend their time answering such polls in the first place, as well as those who hang out in the News discussion section) is made up mostly of slightly older, slight more right-wing people on average. I don't think it's totally accurate of course, but it's hard to get a better indicator of how AB members are distributed by age and politics.
the results of tomorrow's referendum could well be another indicator of the divide between AB and the UK at large. Even if it does go in favour of Leave, I highly doubt anyone here seriously believes that it would be 70-30 or so to Leave...