Specifically, polls that make conservatives look foolish.
"A new poll showed that nearly one in five people, or 18 percent, believe Obama is Muslim. That was up from 11 percent who said so in March 2009. The survey also showed that just 34 percent said Obama is Christian, down from 48 percent who said so last year. The largest share of people, 43 percent, said they don't know his religion." (Quotes from Yahoo! News.)
Now, this isn't a poll of just conservatives. This is a poll of everybody. But we all know who disseminates these kinds of foundless rumors, don't we?
But here is the part that's particularly fun.
"The Pew poll found that about three in 10 of Obama's fiercest political rivals, Republicans and conservatives, say he is a Muslim. That is up significantly from last year and far higher than the share of Democrats and liberals who say so."
IOW, nearly twice as many conservatives are plain wrong on this point compared to the entire population.
Of course, this is all just a distraction from the bigger question: why does it matter? Is it so terrible, the thought of having a Muslim president?
It's funny that conservatives are wrong. It's scary that they care in the first place.