Yes it is. Although the "validity" of poll questions are always questionable (they may be measuring something unintended), the "accuracy" of a poll is mathematically provable relative to sample size. The other major concern is if the sample represents the population. That's managed in a number of ways, either by randomizing the sample or by adjusting it to match the population demographics.
Online polls do none of that. At their absolute BEST, they represent the readership of whatever website they're posted at that are willing to click on some unscientific nonsense. They're skewed by site content, Internet demographics, poll playing demographics, and cheaters.
I suggest you don't compare that crap to a professional poll unless you want to be compared to a flat-earther.
exactly, and where are the demographic breakdowns of the gallup polls, how are those polls weighted? and do they actually represent the demographics of the popluation?, I have seen NONE of the political demographics of the polls from gallup etc. for all you know the gallup poll that shows McCain neck and neck could be weighted more towards democrats and if that was the case while the poll shows it neck and neck if the poll was weighted say 60% dems and 40% gop neck and neck would be very bad for Obama