Here's the source article on Comscore:
What it all means I'm not sure but for February on my sites I still only get 4.3% from Bing and 80% from Google. That doesn't match at all the figures produced by Comscore. And a quick but reasonably accurate check shows that I'm ranking almost the same for top terms in Bing and Google - spookily so!
My sites are UK based though and Comscore is only looking at US figures. They are missing a huge chunk of the world, I think it's called Europe. Without Europe (and others like Russia, Japan etc), the figures are meaningless.
What share does Bing have now according to your stats?