Pundits talk about the value of Yahoo's Asian investments — $12 a share and rising, given this morning's runup in the value of Yahoo Japan and Alibaba — as if they were pork-belly commodities. And yet it's hard to imagine Yahoo thriving when divorced from the vast markets of China and Japan. Yahoo owns 31 percent of Yahoo Japan and 40 percent of Alibaba, the operator of Yahoo China. To have a compelling worldwide growth story that matches Google's, Yahoo — under anyone's ownership — will need to win back those properties someday. Of all Yahoo's potential buyers, only Microsoft has the capital to acquire those stakes with comfort, and reunite them with their troubled American parent.