Is Dunn the only board member to step down?
No. Dunn is actually staying on the board as a director, but board members Tom Perkins and George Keyworth have resigned their board positions. Perkins stepped down in May in protest over the investigation into media leaks. It was his complaints that prompted a subsequent inquiry into methods used in that investigation. Keyworth was pinpointed as a source of the leaks in May, but refused to step down at that time. He resigned on Tuesday, effective immediately.