I wonder how it is possible for a bitmap font to have underscore appear as negative when it is crossing descenders. An example of this would be Group 94 website (click on other news items to see ones that have links with descenders).
Links in the right column text appear with negative underscore, which makes descenders more visible. Can this be achieved within a TTF file itself or takes some trickery, like custom underscored font replacing the regular one after text is loaded?