This chart has been making the rounds on the conservative blogs. Eric Kleefeld asked Mark Blumenthal about it:
"If Obama now has more strong detractors than strong supporters, that is politically meaningful (though contrary to the results of the recent ABC/Washington Post polls, to pick one example)," said Blumenthal. "But to report only those who strongly approve or strongly disapprove of Obama while neglecting mention of the aggregate numbers strikes me as more political spin than analysis."
And he also talked to Rasmussen himself:
Scott Rasmussen defended the index to me. He said he began breaking out the strong approval-disapproval numbers late in 2008, originally for the simple purpose of differentiating himself from Gallup after they got in on the daily tracking gig that had previously been his sole domain. And while he agrees that overall approval will be by far the more important number in 2012, he also thinks that for now the intensity of feeling can have a serious impact on policy discussion and political outcomes.