It is the bane of many female subway riders. It is a scourge tracked on blogs and on Twitter. And it has a name almost as distasteful as the practice itself. It is manspreading, the lay-it-all-out sitting style that more than a few men see as their inalienable underground right. Now passengers who consider such inelegant male posture as infringing on their sensibilities — not to mention their share of subway space — have a new ally: the Metropolitan Transportation Authority. Taking on manspreading for the first time, the authority is set to unveil public service ads that encourage men...