Billboard sales around the region are undergoing a renaissance, as the old-school advertising format benefits from the technology froth, with companies jockeying for their piece of skyline fame and attention. Surging demand has led to a jarring sight for those driving on the highway these days — a 50-foot picture of a pasty software engineer, lying provocatively on his side, showing a bit of chest hair and wearing only his underwear. Outfront Media Inc., the former CBS Corp.