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The success of both the smears and Obama's refutations lie in repetition. By way of example: Bush convinced Americans that Iraq was involved in 9-11 through sophisticated media strategies, but what it boiled down to was repetition. If you repeat the lie often enough people will believe.
Certainly Obama's only method of information control should not rest in these websites alone. But anything that allows for repetition of information is probably good for him.
But, yeah, I agree that it is not a good idea to ask readers to give the Obama campaign their passwords. That's weird, and anybody with any understanding of internet safety would agree.