The news that the Mercury News would have its fourth owner in four years came as a shock to Mercury employees, though not entirely a surprise. MediaNews’ debt service issues were well known, and a first quarter restructuring was anticipated. Unlike past announcements, however, the shoe-dropping came without warning. “This thing blindsided everyone in the newsroom,” one knowledgeable insider said.  The announcement arrived, along with an FAQ, at 4:30pm Friday, as the staff was getting ready to head out for a three-day weekend.