If the decisions made by corporate boards of directors can indicate where a company wants to be focusing, Amazon’s board just made an interesting move. The company announced on Thursday that Andrew Ng, known for building AI at large tech companies, is joining its board of directors. The company also said that Judy McGrath — best known for her work as a long-time TV executive, running MTV and helping Viacom become a media powerhouse — will be stepping down as a director. Taken together, the two m...